Hamachi - Hamachi is a VPN service scaled to the unique needs of business owners.
OverPlay - OverPlay is an excellent smart DNS and high-speed VPN service provider across the globe.
ZeroTier - Extremely simple P2P Encrypted VPN
Bitmask - Bitmask is an open source application to provide easy and secure encrypted communication.
OpenVPN - OpenVPN - The Open Source VPN
FreePN - FreePN is the first open-source peer-to-peer VPN service. It's also fast, secure, and completely free.