Tor Browser - Tor is free software for enabling anonymous communication.
ProxAllium - ProxAllium is a FOSS GUI wrapper for Tor.
Proxifier - Proxifier extends the advantages of a proxy server to network applications that don't natively support it.
I2P - The I2P network provides strong privacy protections for communication over the Internet.
Vidalia - Vidalia is a cross-platform graphical controller for the Tor software, built using the Qt framework.
anonymoX - AnonymoX is an initiative for anonymization on the internet.