Coscreen.co

CoScreen™ turns your secondary display into your joint team desktop. Share windows via drag & drop, collaborate remotely via mouse & keyboard, each user gets their own mouse pointer. Now available for macOS and entirely free during our beta.

Kinda neat looking. What with all the RDP Solutions being kinda old news and webRTC kinda leaky maybe this works a little bit better than other offerings, either way, work downloading and trying it with your team at the moment because it's completely free -- encrypted, AES 256 and HTTPS/SSL.