Web browser extensions
FoxyProxy - a set of proxy management tools for Firefox, Thunderbird, Seamonkey, and Songbird.
Proxifier - a program that allows network applications that do not support working through proxy servers to operate through an HTTPS or SOCKS proxy or a chain of proxy servers
FreeCap - is a program for transparency redirect connections from programs through SOCKS server. In fact that some programs hasn't native SOCKS support (for example Internet Explorer), In this case FreeCap will be helpful, transparently redirect all connections requests through SOCKS server.
Sockschain - a program that allows to work with any Internet service through a chain of SOCKS or HTTP proxies to hide the real IP-address. SocksChain can function as a usual SOCKS-server that transmits queries through a chain of proxies. SocksChain can be used with client programs that do not support the SOCKS protocol, but work with one TCP-connection, such as TELNET, HTTP, IRC... (FTP uses 2 connections). And your IP-address will not be seen in the server's logs or mail headers.
tinyproxy - a lightweight HTTP/SSL proxy
proxytunnel - program that connects stdin and stdout to a server somewhere on the network, through a standard HTTPS proxy
proxychains - force any tcp connections to flow through a proxy (or proxy chain)
dircproxy - an IRC proxy server
squid - A full-featured web proxy cache
tsocks - transparent SOCKS v4 proxying library
dante - A free socks4,5 and msproxy implementation
privoxy - A web proxy with advanced filtering capabilities for protecting privacy against Internet junk
tor - Anonymizing overlay network for TCP
3proxy - really tiny cross-platform proxy servers set
Some useful applications are missed? Contact us!