RainWallpaper is a free software for Windows that allows you to create extraordinary animated desktop backgrounds for Windows.
The user can also download already created wallpapers, which can be customized.
Funds can include 2D or 3D animations, web pages, videos, all of which provide an unparalleled experience when you add computer mouse interaction and even special effects.
According to its creators, Rainsoft, does not use much CPU, as well as much RAM, which is the first thing I thought when I started reading about this software.
The creators of this software have a gallery in DevianArt to which the user can upload their creations to share with other users of the software. Users can also download wallpapers from the online gallery that is integrated into the same software.
Link | Rainsoft
The following video includes a tutorial on how to create an animated desktop background and how to upload it to the gallery in DevianArt.