Rainmeter, Conky, Widgy Widgets, Widgetable, MenuMeters, 8GadgetPack, gDesklets, MenuMeters for El Capitan, Cysboard, MiniUsage, GeekTool, GKrellM, screenstyler, Screenlets, Eww, Samurize, Desktop Info, Microsoft Gadgets, KDE Plasma Workspaces, Nerdtool, myBoard, Yahoo Widget, AveDesk, Open Sidebar, Moo0 System Monitor, ThemeWidgets are some alternatives to XWidget.