[aidenn0]

Nomachine's server and client are closed-source but work great.

For open-source solution for quickly remoting into an existing display, I use freerdp-shadow-cli which is way more stable than x11vnc and uses the RDP protocol instead.

[RealStickman_]

Nomachine used to be open source. X2Go is the open source continuation of that.

[aidenn0]

I think their current version is unrelated to what is now x2go