Husarnet

Husarnet is a different kind of VPN - it connects your devices, not your networks.
It runs on your computers, servers, Raspberry Pis and even on real tiny microcontrollers!
It's a great tool for remote development, out of band access, IoT and robotics.
It creates a globe-wide IPv6 network, where addresses are based on your public keys, and access is configured with 1:1 ACLs.
You can even share access to your devices with your coworkers with zero configuration on the host itself.