I see files in my assets list I don’t recognize

If a collection was shared with you, you’ll see those assets in your asset list.

When you select Assets from the navigation menu, you see all assets that you can access. This includes any assets from a collection that was shared with you. You can find the collection where an asset is managed. Double-click on the asset to view the properties of the item. The collection and any tags associated with the asset are displayed.