This is my list of  3rd party Desktop sharing services/clients i have found on the internet. Some are free and some are really expensive.

• Teamviewer
• Gotomypc
• Join.me
• Avast has remote control built in. Both PCs need Avast installed
• Gotoassist
• Hamachi free
• Open VPN + RDP
• No Machine 4
• Meraki Systems Manager
• VNC
• RealVNC
• UltraVNC
• Jumpdesktop.com/free-remote-desktop
• Chrome remote desktop
• Gbridge
• Spiceworks + RDP
• Server 2003 + RDP Etc..
• Aeroadmi.com
• AMMY admin
• RDP
• Centra Stage ©
• Mikogo ©