ModernFlyouts is a Microsoft Store app that aims to replace the built-in flyouts with a Fluent Design-based alternative. Lively Wallpaper lets you turn video, GIF, HTML and HTML into Windows desktop wallpaper. BeautySearch lets you enable rounded corners within the Windows Search results using JavaScript. You can also use Lively wallpaper to create your own wallpapers and the app will automatically pause the playback of the animated content when full screen application/games are running to reduce memory usage.
Source: https://www.bleepingcomputer.com/news/microsoft/personalize-your-windows-10-desktop-with-these-three-apps/