A package of visual themes for desktops, from ttuuxxx. Installs in the Menu / Desktop / Chtheme GTK theme chooser entry.

Makes random changes to desktop wallpaper at intervals set by the user. Choose from backgrounds or any other folder, even from online. More information is available here.

Standard on most Linux versions; here's one for Puppy. It had some issues that were resolved here, and includes those fixes.