Apps with 'Support for Multiple protocols' feature
Tor is free software and an open network that helps you defend against traffic analysis, a form of network surveillance that threatens personal freedom and privacy, confidential business activities and relationships, and state security.
Pidgin is an easy to use, multi-protocol chat client client used by millions. Connect to AIM, MSN, Yahoo, XMPP, and more chat networks all at once.
Jitsi (previously SIP Communicator) is an audio/video and chat communicator with full encryption that supports protocols such as SIP, XMPP/Jabber, ICQ/AIM, Windows Live, Yahoo!
Android, BSD, Linux, and Windows open source multimedia download manager.
aria2 is a multi-protocol & multi-source, cross platform download utility. The supported protocols are HTTP(S), FTP, BitTorrent (DHT, PEX, MSE/PE), and Metalink.
Free, open source and cross platform messaging and emailing app that combines common web applications into one.
Open source and copyleft remote desktop client for Linux and BSD that supports plugins.
An advanced terminal that gives Windows users a powerful, Unix-like command-line experience.
Franz is a free messaging app / former Emperor of Austria and combines chat & messaging services into one application. Franz currently supports Slack, WhatsApp, WeChat, HipChat and many more. You can download Franz for Mac, Windows & Linux.
mRemoteNG is a fork of mRemote, an open source, tabbed, multi-protocol, remote connections manager.
SoftEther VPN is one of the world's most powerful and easy-to-use multi-protocol VPN software.
"empowering the smart home" - vendor and technology agnostic open source home automation.
Adium is a free and open source instant messaging application for Mac OS X, written using Mac OS Xs Cocoa API, released under the GNU GPL and developed by the Adium team.
Miranda IM is the smaller, faster, easier instant messenger with support for multiple protocols.
Shareaza is the most luxurious and sophisticated file sharing system you'll find.