diff --git a/src/ol/Collection.js b/src/ol/Collection.js
index 79ee531a3d..276d4180f8 100644
--- a/src/ol/Collection.js
+++ b/src/ol/Collection.js
@@ -18,11 +18,12 @@ const Property = {
  * @classdesc
  * Events emitted by {@link module:ol/Collection~Collection} instances are instances of this
  * type.
+ * @template T
  */
 export class CollectionEvent extends Event {
   /**
    * @param {import("./CollectionEventType.js").default} type Type.
-   * @param {*} element Element.
+   * @param {T} element Element.
    * @param {number} index The index of the added or removed element.
    */
   constructor(type, element, index) {
@@ -30,7 +31,7 @@ export class CollectionEvent extends Event {
 
     /**
      * The element that is added to or removed from the collection.
-     * @type {*}
+     * @type {T}
      * @api
      */
     this.element = element;
@@ -45,10 +46,11 @@ export class CollectionEvent extends Event {
 }
 
 /***
+ * @template T
  * @template Return
  * @typedef {import("./Observable").OnSignature<import("./Observable").EventTypes, import("./events/Event.js").default, Return> &
  *   import("./Observable").OnSignature<import("./ObjectEventType").Types|'change:length', import("./Object").ObjectEvent, Return> &
- *   import("./Observable").OnSignature<'add'|'remove', CollectionEvent, Return> &
+ *   import("./Observable").OnSignature<'add'|'remove', CollectionEvent<T>, Return> &
  *   import("./Observable").CombinedOnSignature<import("./Observable").EventTypes|import("./ObjectEventType").Types|
  *     'change:length'|'add'|'remove',Return>} CollectionOnSignature
  */
@@ -81,17 +83,17 @@ class Collection extends BaseObject {
     super();
 
     /***
-     * @type {CollectionOnSignature<import("./events").EventsKey>}
+     * @type {CollectionOnSignature<T, import("./events").EventsKey>}
      */
     this.on;
 
     /***
-     * @type {CollectionOnSignature<import("./events").EventsKey>}
+     * @type {CollectionOnSignature<T, import("./events").EventsKey>}
      */
     this.once;
 
     /***
-     * @type {CollectionOnSignature<void>}
+     * @type {CollectionOnSignature<T, void>}
      */
     this.un;
 
@@ -264,7 +266,9 @@ class Collection extends BaseObject {
     this.array_.splice(index, 1);
     this.updateLength_();
     this.dispatchEvent(
-      new CollectionEvent(CollectionEventType.REMOVE, prev, index)
+      /** @type {CollectionEvent<T>} */ (
+        new CollectionEvent(CollectionEventType.REMOVE, prev, index)
+      )
     );
     return prev;
   }
@@ -290,10 +294,14 @@ class Collection extends BaseObject {
     const prev = this.array_[index];
     this.array_[index] = elem;
     this.dispatchEvent(
-      new CollectionEvent(CollectionEventType.REMOVE, prev, index)
+      /** @type {CollectionEvent<T>} */ (
+        new CollectionEvent(CollectionEventType.REMOVE, prev, index)
+      )
     );
     this.dispatchEvent(
-      new CollectionEvent(CollectionEventType.ADD, elem, index)
+      /** @type {CollectionEvent<T>} */ (
+        new CollectionEvent(CollectionEventType.ADD, elem, index)
+      )
     );
   }
 
diff --git a/src/ol/PluggableMap.js b/src/ol/PluggableMap.js
index 3fa410d5a1..a159feb9ed 100644
--- a/src/ol/PluggableMap.js
+++ b/src/ol/PluggableMap.js
@@ -439,7 +439,7 @@ class PluggableMap extends BaseObject {
     this.controls.addEventListener(
       CollectionEventType.ADD,
       /**
-       * @param {import("./Collection.js").CollectionEvent} event CollectionEvent.
+       * @param {import("./Collection.js").CollectionEvent<import("./control/Control.js").default>} event CollectionEvent
        */
       function (event) {
         event.element.setMap(this);
@@ -449,7 +449,7 @@ class PluggableMap extends BaseObject {
     this.controls.addEventListener(
       CollectionEventType.REMOVE,
       /**
-       * @param {import("./Collection.js").CollectionEvent} event CollectionEvent.
+       * @param {import("./Collection.js").CollectionEvent<import("./control/Control.js").default>} event CollectionEvent.
        */
       function (event) {
         event.element.setMap(null);
@@ -459,7 +459,7 @@ class PluggableMap extends BaseObject {
     this.interactions.addEventListener(
       CollectionEventType.ADD,
       /**
-       * @param {import("./Collection.js").CollectionEvent} event CollectionEvent.
+       * @param {import("./Collection.js").CollectionEvent<import("./interaction/Interaction.js").default>} event CollectionEvent.
        */
       function (event) {
         event.element.setMap(this);
@@ -469,7 +469,7 @@ class PluggableMap extends BaseObject {
     this.interactions.addEventListener(
       CollectionEventType.REMOVE,
       /**
-       * @param {import("./Collection.js").CollectionEvent} event CollectionEvent.
+       * @param {import("./Collection.js").CollectionEvent<import("./interaction/Interaction.js").default>} event CollectionEvent.
        */
       function (event) {
         event.element.setMap(null);
@@ -479,25 +479,20 @@ class PluggableMap extends BaseObject {
     this.overlays_.addEventListener(
       CollectionEventType.ADD,
       /**
-       * @param {import("./Collection.js").CollectionEvent} event CollectionEvent.
+       * @param {import("./Collection.js").CollectionEvent<import("./Overlay.js").default>} event CollectionEvent.
        */
       function (event) {
-        this.addOverlayInternal_(
-          /** @type {import("./Overlay.js").default} */ (event.element)
-        );
+        this.addOverlayInternal_(event.element);
       }.bind(this)
     );
 
     this.overlays_.addEventListener(
       CollectionEventType.REMOVE,
       /**
-       * @param {import("./Collection.js").CollectionEvent} event CollectionEvent.
+       * @param {import("./Collection.js").CollectionEvent<import("./Overlay.js").default>} event CollectionEvent.
        */
       function (event) {
-        const overlay = /** @type {import("./Overlay.js").default} */ (
-          event.element
-        );
-        const id = overlay.getId();
+        const id = event.element.getId();
         if (id !== undefined) {
           delete this.overlayIdIndex_[id.toString()];
         }
@@ -1709,7 +1704,12 @@ function createOptionsInternal(options) {
     options.layers &&
     typeof (/** @type {?} */ (options.layers).getLayers) === 'function'
       ? /** @type {LayerGroup} */ (options.layers)
-      : new LayerGroup({layers: /** @type {Collection} */ (options.layers)});
+      : new LayerGroup({
+          layers:
+            /** @type {Collection<import("./layer/Base.js").default>|Array<import("./layer/Base.js").default>} */ (
+              options.layers
+            ),
+        });
   values[MapProperty.LAYERGROUP] = layerGroup;
 
   values[MapProperty.TARGET] = options.target;
@@ -1717,6 +1717,7 @@ function createOptionsInternal(options) {
   values[MapProperty.VIEW] =
     options.view instanceof View ? options.view : new View();
 
+  /** @type {Collection<import("./control/Control.js").default>} */
   let controls;
   if (options.controls !== undefined) {
     if (Array.isArray(options.controls)) {
@@ -1726,10 +1727,11 @@ function createOptionsInternal(options) {
         typeof (/** @type {?} */ (options.controls).getArray) === 'function',
         47
       ); // Expected `controls` to be an array or an `import("./Collection.js").Collection`
-      controls = /** @type {Collection} */ (options.controls);
+      controls = options.controls;
     }
   }
 
+  /** @type {Collection<import("./interaction/Interaction").default>} */
   let interactions;
   if (options.interactions !== undefined) {
     if (Array.isArray(options.interactions)) {
@@ -1740,10 +1742,11 @@ function createOptionsInternal(options) {
           'function',
         48
       ); // Expected `interactions` to be an array or an `import("./Collection.js").Collection`
-      interactions = /** @type {Collection} */ (options.interactions);
+      interactions = options.interactions;
     }
   }
 
+  /** @type {Collection<import("./Overlay.js").default>} */
   let overlays;
   if (options.overlays !== undefined) {
     if (Array.isArray(options.overlays)) {
diff --git a/src/ol/control.js b/src/ol/control.js
index 358083e6e4..847109d3e0 100644
--- a/src/ol/control.js
+++ b/src/ol/control.js
@@ -50,6 +50,7 @@ export {default as ZoomToExtent} from './control/ZoomToExtent.js';
 export function defaults(opt_options) {
   const options = opt_options ? opt_options : {};
 
+  /** @type {Collection<import("./control/Control.js").default>} */
   const controls = new Collection();
 
   const zoomControl = options.zoom !== undefined ? options.zoom : true;
diff --git a/src/ol/interaction.js b/src/ol/interaction.js
index f4500568e5..6d354e39a3 100644
--- a/src/ol/interaction.js
+++ b/src/ol/interaction.js
@@ -84,6 +84,7 @@ export {default as Translate} from './interaction/Translate.js';
 export function defaults(opt_options) {
   const options = opt_options ? opt_options : {};
 
+  /** @type {Collection<import("./interaction/Interaction.js").default>} */
   const interactions = new Collection();
 
   const kinetic = new Kinetic(-0.005, 0.05, 100);
diff --git a/src/ol/interaction/Modify.js b/src/ol/interaction/Modify.js
index fe184f355d..4fccb73ab3 100644
--- a/src/ol/interaction/Modify.js
+++ b/src/ol/interaction/Modify.js
@@ -361,6 +361,7 @@ class Modify extends PointerInteraction {
      */
     this.hitDetection_ = null;
 
+    /** @type {Collection<Feature>} */
     let features;
     if (options.features) {
       features = options.features;
@@ -574,11 +575,11 @@ class Modify extends PointerInteraction {
   }
 
   /**
-   * @param {import("../Collection.js").CollectionEvent} evt Event.
+   * @param {import("../Collection.js").CollectionEvent<Feature>} evt Event.
    * @private
    */
   handleFeatureAdd_(evt) {
-    this.addFeature_(/** @type {Feature} */ (evt.element));
+    this.addFeature_(evt.element);
   }
 
   /**
@@ -594,12 +595,11 @@ class Modify extends PointerInteraction {
   }
 
   /**
-   * @param {import("../Collection.js").CollectionEvent} evt Event.
+   * @param {import("../Collection.js").CollectionEvent<Feature>} evt Event.
    * @private
    */
   handleFeatureRemove_(evt) {
-    const feature = /** @type {Feature} */ (evt.element);
-    this.removeFeature_(feature);
+    this.removeFeature_(evt.element);
   }
 
   /**
diff --git a/src/ol/interaction/Select.js b/src/ol/interaction/Select.js
index 556fcbea4e..6efee1180f 100644
--- a/src/ol/interaction/Select.js
+++ b/src/ol/interaction/Select.js
@@ -75,7 +75,7 @@ const SelectEventType = {
  * @property {boolean} [multi=false] A boolean that determines if the default
  * behaviour should select only single features or all (overlapping) features at
  * the clicked map position. The default of `false` means single select.
- * @property {import("../Collection.js").default<import("../Feature.js").default>} [features]
+ * @property {Collection<Feature>} [features]
  * Collection where the interaction will place selected features. Optional. If
  * not set the interaction will create a collection. In any case the collection
  * used by the interaction is returned by
@@ -245,7 +245,7 @@ class Select extends Interaction {
 
     /**
      * @private
-     * @type {import("../Collection.js").default}
+     * @type {Collection<Feature>}
      */
     this.features_ = options.features || new Collection();
 
@@ -290,7 +290,7 @@ class Select extends Interaction {
 
   /**
    * Get the selected features.
-   * @return {import("../Collection.js").default<import("../Feature.js").default>} Features collection.
+   * @return {Collection<Feature>} Features collection.
    * @api
    */
   getFeatures() {
@@ -367,7 +367,7 @@ class Select extends Interaction {
   }
 
   /**
-   * @param {import("../Collection.js").CollectionEvent} evt Event.
+   * @param {import("../Collection.js").CollectionEvent<Feature>} evt Event.
    * @private
    */
   addFeature_(evt) {
@@ -396,13 +396,12 @@ class Select extends Interaction {
   }
 
   /**
-   * @param {import("../Collection.js").CollectionEvent} evt Event.
+   * @param {import("../Collection.js").CollectionEvent<Feature>} evt Event.
    * @private
    */
   removeFeature_(evt) {
-    const feature = evt.element;
     if (this.style_) {
-      this.restorePreviousStyle_(feature);
+      this.restorePreviousStyle_(evt.element);
     }
   }
 
@@ -414,7 +413,7 @@ class Select extends Interaction {
   }
 
   /**
-   * @param {import("../Feature.js").default} feature Feature
+   * @param {Feature} feature Feature
    * @private
    */
   applySelectedStyle_(feature) {
@@ -426,7 +425,7 @@ class Select extends Interaction {
   }
 
   /**
-   * @param {import("../Feature.js").default} feature Feature
+   * @param {Feature} feature Feature
    * @private
    */
   restorePreviousStyle_(feature) {
@@ -450,7 +449,7 @@ class Select extends Interaction {
   }
 
   /**
-   * @param {import("../Feature.js").default} feature Feature.
+   * @param {Feature} feature Feature.
    * @private
    */
   removeFeatureLayerAssociation_(feature) {
@@ -476,12 +475,12 @@ class Select extends Interaction {
     const features = this.getFeatures();
 
     /**
-     * @type {Array<import("../Feature.js").default>}
+     * @type {Array<Feature>}
      */
     const deselected = [];
 
     /**
-     * @type {Array<import("../Feature.js").default>}
+     * @type {Array<Feature>}
      */
     const selected = [];
 
diff --git a/src/ol/interaction/Snap.js b/src/ol/interaction/Snap.js
index 4395fb8e11..794a9ce6fa 100644
--- a/src/ol/interaction/Snap.js
+++ b/src/ol/interaction/Snap.js
@@ -45,7 +45,7 @@ import {listen, unlistenByKey} from '../events.js';
  */
 
 /**
- * @param  {import("../source/Vector.js").VectorSourceEvent|import("../Collection.js").CollectionEvent} evt Event.
+ * @param  {import("../source/Vector.js").VectorSourceEvent|import("../Collection.js").CollectionEvent<import("../Feature.js").default>} evt Event.
  * @return {import("../Feature.js").default} Feature.
  */
 function getFeatureFromEvent(evt) {
@@ -55,11 +55,13 @@ function getFeatureFromEvent(evt) {
     return /** @type {import("../source/Vector.js").VectorSourceEvent} */ (evt)
       .feature;
   } else if (
-    /** @type {import("../Collection.js").CollectionEvent} */ (evt).element
+    /** @type {import("../Collection.js").CollectionEvent<import("../Feature.js").default>} */ (
+      evt
+    ).element
   ) {
-    return /** @type {import("../Feature.js").default} */ (
-      /** @type {import("../Collection.js").CollectionEvent} */ (evt).element
-    );
+    return /** @type {import("../Collection.js").CollectionEvent<import("../Feature.js").default>} */ (
+      evt
+    ).element;
   }
 }
 
@@ -261,6 +263,7 @@ class Snap extends PointerInteraction {
    * @private
    */
   getFeatures_() {
+    /** @type {import("../Collection.js").default<import("../Feature.js").default>|Array<import("../Feature.js").default>} */
     let features;
     if (this.features_) {
       features = this.features_;
@@ -284,7 +287,7 @@ class Snap extends PointerInteraction {
   }
 
   /**
-   * @param {import("../source/Vector.js").VectorSourceEvent|import("../Collection.js").CollectionEvent} evt Event.
+   * @param {import("../source/Vector.js").VectorSourceEvent|import("../Collection.js").CollectionEvent<import("../Feature.js").default>} evt Event.
    * @private
    */
   handleFeatureAdd_(evt) {
@@ -293,7 +296,7 @@ class Snap extends PointerInteraction {
   }
 
   /**
-   * @param {import("../source/Vector.js").VectorSourceEvent|import("../Collection.js").CollectionEvent} evt Event.
+   * @param {import("../source/Vector.js").VectorSourceEvent|import("../Collection.js").CollectionEvent<import("../Feature.js").default>} evt Event.
    * @private
    */
   handleFeatureRemove_(evt) {
diff --git a/src/ol/layer/Group.js b/src/ol/layer/Group.js
index 72cbf0c855..4361c99387 100644
--- a/src/ol/layer/Group.js
+++ b/src/ol/layer/Group.js
@@ -66,7 +66,7 @@ export class GroupEvent extends Event {
  * visible.
  * @property {number} [maxZoom] The maximum view zoom level (inclusive) at which this layer will
  * be visible.
- * @property {Array<import("./Base.js").default>|import("../Collection.js").default<import("./Base.js").default>} [layers] Child layers.
+ * @property {Array<import("./Base.js").default>|Collection<import("./Base.js").default>} [layers] Child layers.
  * @property {Object<string, *>} [properties] Arbitrary observable properties. Can be accessed with `#get()` and `#set()`.
  */
 
@@ -214,26 +214,22 @@ class LayerGroup extends BaseLayer {
   }
 
   /**
-   * @param {import("../Collection.js").CollectionEvent} collectionEvent CollectionEvent.
+   * @param {import("../Collection.js").CollectionEvent<import("./Base.js").default>} collectionEvent CollectionEvent.
    * @private
    */
   handleLayersAdd_(collectionEvent) {
-    const layer = /** @type {import("./Base.js").default} */ (
-      collectionEvent.element
-    );
+    const layer = collectionEvent.element;
     this.registerLayerListeners_(layer);
     this.dispatchEvent(new GroupEvent('addlayer', layer));
     this.changed();
   }
 
   /**
-   * @param {import("../Collection.js").CollectionEvent} collectionEvent CollectionEvent.
+   * @param {import("../Collection.js").CollectionEvent<import("./Base.js").default>} collectionEvent CollectionEvent.
    * @private
    */
   handleLayersRemove_(collectionEvent) {
-    const layer = /** @type {import("./Base.js").default} */ (
-      collectionEvent.element
-    );
+    const layer = collectionEvent.element;
     const key = getUid(layer);
     this.listenerKeys_[key].forEach(unlistenByKey);
     delete this.listenerKeys_[key];
@@ -244,13 +240,13 @@ class LayerGroup extends BaseLayer {
   /**
    * Returns the {@link module:ol/Collection~Collection collection} of {@link module:ol/layer/Layer~Layer layers}
    * in this group.
-   * @return {!import("../Collection.js").default<import("./Base.js").default>} Collection of
+   * @return {!Collection<import("./Base.js").default>} Collection of
    *   {@link module:ol/layer/Base~BaseLayer layers} that are part of this group.
    * @observable
    * @api
    */
   getLayers() {
-    return /** @type {!import("../Collection.js").default<import("./Base.js").default>} */ (
+    return /** @type {!Collection<import("./Base.js").default>} */ (
       this.get(Property.LAYERS)
     );
   }
@@ -258,7 +254,7 @@ class LayerGroup extends BaseLayer {
   /**
    * Set the {@link module:ol/Collection~Collection collection} of {@link module:ol/layer/Layer~Layer layers}
    * in this group.
-   * @param {!import("../Collection.js").default<import("./Base.js").default>} layers Collection of
+   * @param {!Collection<import("./Base.js").default>} layers Collection of
    *   {@link module:ol/layer/Base~BaseLayer layers} that are part of this group.
    * @observable
    * @api
diff --git a/src/ol/source/Vector.js b/src/ol/source/Vector.js
index 426ef36aa2..1f518d0ef4 100644
--- a/src/ol/source/Vector.js
+++ b/src/ol/source/Vector.js
@@ -302,10 +302,7 @@ class VectorSource extends Source {
     /** @type {Array<import("../Feature.js").default<Geometry>>} */
     let features;
     if (Array.isArray(options.features)) {
-      features =
-        /** @type {Array<import("../Feature.js").default<Geometry>>} */ (
-          options.features
-        );
+      features = options.features;
     } else if (options.features) {
       collection = options.features;
       features = collection.getArray();
@@ -501,16 +498,12 @@ class VectorSource extends Source {
     collection.addEventListener(
       CollectionEventType.ADD,
       /**
-       * @param {import("../Collection.js").CollectionEvent} evt The collection event
+       * @param {import("../Collection.js").CollectionEvent<import("../Feature.js").default<Geometry>>} evt The collection event
        */
       function (evt) {
         if (!modifyingCollection) {
           modifyingCollection = true;
-          this.addFeature(
-            /** @type {import("../Feature.js").default<Geometry>} */ (
-              evt.element
-            )
-          );
+          this.addFeature(evt.element);
           modifyingCollection = false;
         }
       }.bind(this)
@@ -518,16 +511,12 @@ class VectorSource extends Source {
     collection.addEventListener(
       CollectionEventType.REMOVE,
       /**
-       * @param {import("../Collection.js").CollectionEvent} evt The collection event
+       * @param {import("../Collection.js").CollectionEvent<import("../Feature.js").default<Geometry>>} evt The collection event
        */
       function (evt) {
         if (!modifyingCollection) {
           modifyingCollection = true;
-          this.removeFeature(
-            /** @type {import("../Feature.js").default<Geometry>} */ (
-              evt.element
-            )
-          );
+          this.removeFeature(evt.element);
           modifyingCollection = false;
         }
       }.bind(this)