Gnome Screensaver is described as 'gnome-screensaver is a new screensaver that can replace xscreensaver. It is designed to integrate well with the desktop and provide a control interface that is desktop neutral' and is an app in the OS & Utilities category. There are five alternatives to Gnome Screensaver for Mac, Windows, Linux, Android and XScreenSaver. The best alternative is Fliqlo Screensaver, which is free. Other great apps like Gnome Screensaver are Xscreensaver for Windows (Paid), XScreenSaver (Free, Open Source), Briblo Screensaver (Free) and Brooklyn Screensaver (Free, Open Source).
XScreenSaverWin is a Windows port of XScreenSaver. 204 screensavers in XScreenSaver were ported. A few of the screensavers have some issues. Check the status page for more. (This app is no longer free or open source starting with v0.80.)