Remote desktop software that uses GTK

Remmina is a free and open source remote desktop client for POSIX-based computer operating systems. It supports the Remote Desktop Protocol (RDP), VNC, NX, XDMCP, SPICE, X2Go and SSH protocols and uses FreeRDP as foundation.

Vinagre is a discontinued VNC, SSH, RDP and SPICE client for the GNOME desktop environment, superseded by GNOME Connections. Vinagre was included in GNOME 2.22. It has several features, like the ability to connect to multiple servers simultaneously and to switch between them using tabs, VNC servers browsing and bookmarking. In version 2.29, Vinagre added controlling frame compression, better scaling and color depth. Version 2.30 added improved SSH tunneling and better support for copy-paste features between client and server.