Note: You can also use a Proxy, SSH Tunneling, and a VPN KillSwitch.
WindScribe – Windscribe is the only free VPN + Firewall that you can use on Linux.
Pritunl – Free open source enterprise distributed VPN server. Virtualize your private networks across datacenters and provide simple remote access in minutes.
ProtonVPN – is a security focused FREE VPN service, developed by CERN and MIT scientists.
OpenVPN – provides flexible VPN solutions for businesses to secure all data communications and extend private network services while maintaining security.
Speedify – provides channel bonding, link aggregation & VPN software to improve the reliability, speed & security of Internet data and steaming applications.
VPNBook – is the #1 premium Free VPN Server account provider. US, UK, and offshore VPN servers available.
TorVPN – Easy to use Proxy and VPN services with built in TOR and Onion proxy. Bypass content filters with servers all over the world.
SecurityKISS – Tunnel that redirects all your online data through an impenetrable tunnel to their security gateway.
LibreSwan VPN – is a fork of the Openswan IPsec VPN implementation.
OpenConnect – is an SSL VPN client initially created to support Cisco’s AnyConnect SSL VPN. It has since been ported to support the Juniper SSL VPN (which is now known as Pulse Connect Secure), and to the Palo Alto Networks GlobalProtect SSL VPN.
OpenSwan – provides a complete IPsec implementation for Linux 2.0, 2.2, 2.4 and 2.6 kernels. Openswan, begun as a fork of the now-defunct FreeS/WAN project, continues to use the GNU General Public License.
SoftEther VPN – SoftEther VPN (“SoftEther” means “Software Ethernet”) is one of the world’s most powerful and easy-to-use multi-protocol VPN software. It runs on Windows, Linux, Mac, FreeBSD and Solaris. SoftEther VPN is open source. You can use SoftEther for any personal or commercial use for free charge.
StrongSwan – is a multiplatform IPsec implementation. The focus of the project is on strong authentication mechanisms using X.509 public key certificates and optional secure storage of private keys and certificates on smartcards through a standardized PKCS#11 interface and on TPM 2.0.
TCPCrypt – is a transport layer communication encryption protocol. Unlike prior protocols like TLS, tcpcrypt is implemented as a TCP extension. It was designed by a team of six security and networking experts: Andrea Bittau, Mike Hamburg, Mark Handley, David Mazières, Dan Boneh and Quinn Slack.
Tinc VPN – is a Virtual Private Network (VPN) daemon that uses tunnelling and encryption to create a secure private network between hosts on the Internet. tinc is Free Software and licensed under the GNU General Public License version 2 or later.
VPN Gate – Connect to 6000+ active VPN servers with L2TP/IPsec, OpenVPN, MS-SSTP or SSL-VPN protocol. Academic project by University of Tsukuba, free of charge.
CyberGhost VPN – is a software company that provides a virtual private network for web browsing.