Wallpaper Cosmos is a free app for Android devices that contains a large collection of HD and 4K wallpapers for your home screen or lock screen. The app contains thousands of images and is updated regularly with new content. It's a simple app that doesn't require any extra permissions.

You can download and use it for free, and there are no in-app purchases or advertisements. You can use the app to save your favorite images or set a wallpaper on your home screen or lock screen.

There are different categories of wallpapers such as space, nature, fantasy, animals, and many more.