PRISM break offers a lot of alternatives against proprietary programs and websites: https://www.prism-break.org/
Our recommdations, which i missed on the list:
If you like Google Chrome, but not the spy functions, then we recommend SRWare Iron, which source is based on Google Chromium, but without spy functions.
For GPG, the Firefox plugin WebPG provide inline encryption for messages.
For windows users (but it works also in Wine), Miranda IM is a good multi messenger and don't need much RAM, see also here
Feel free to contribute the list, if you know more free alternatives.