Retroshare establish encrypted connections between you and your friends to create a network of computers, and provides various distributed services on top of it: forums, channels, chat, mail…
VeraCrypt
VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux.
Tor
The Tor software protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world.
YouTube DL GUI
OnionShare is an open source tool for securely and anonymously sending and receiving files using Tor onion services.