Remmina - Remmina is a remote desktop client written in GTK+, aiming to be useful for system administrators and travellers, who need to work with lots of remote computers in front of either large monitors or tiny netbooks.
PuTTY - Popular free terminal application. Mostly used as an SSH client.
Xpra - multi-platform screen and application forwarding system
MobaXterm - Enhanced terminal for Windows with X11 server, tabbed SSH client, network tools and much more
X2Go - Get X2Go. Installing X2Go (client/server). Download X2Go Client (Windows installer (XP and Later), OS X 10. 9 and higher DMG, OS X 10. 10 and higher DMG or macOS 10.
iTerm2 - A terminal emulator for macOS that does amazing things.