LogMeIn Hamachi is a multi platform software (Windows, Mac, Linux) that allows to create a virtual LAN over Internet, so you can play your favourites games that have a LAN mode with your friends all over the world.
GameRanger (for PC and Mac) supports over 500 game titles, only works with its list of supported games.
ZeroTier allows to easily establish VPN connection between two PC. The community version is free with the limit of 100 devices. Android and iOS apps available.
DynVPN another free VPN software that allows to create a LAN network using Internet. Semplice da configurare. Windows, Mac, Linx and Raspberry downloads available.
Radmin VPN provides a secure and fast VPN tunnel.
Wippien another VPN software, has an useful integrated messaging system.