Remmina, UltraViewer, TeamViewer, AnyDesk, RustDesk, Microsoft Remote Desktop, Xrdp, Chrome Remote Desktop, Kasm Workspaces, DWService, MeshCentral, NoMachine, Remotely, Quick Assist, seecreen, eHorus, HopToDesk, RemoteView, screego, FastX, Xpra, ThinLinc, zsoporte, DesktopAssist, Thincast Client, Iperius Remote, Viubo are some alternatives to X2Go.