RUSTDESK
MESHCENTRAL
Apache Guacamole - uses RDP/VNC - its more a gate access control but still usfull.
Remotely
are some other options
i've used pcanywhere, teamviewer, dameware, RDP, teamviewer and beyondtrust, probably a few others as well..
i quiet like BeyondTrust they implemenet the multi monoor well, and some nifty fetures also.
it really depends how you intend to use the remote access and from where, and what fetures you think you need.
do you need paid support? do you want it self hosted? or hosted in the cloud? how technical are you? our you external coming in to internal network? do you need a vpn/do you use a vpn? is it ipv6?
tbh RDP internal is ok, but it is a known attack vector, so dont have rdp enabled on externally facing internet machine ! thats asling for problems.