Nixpkgs is a collection of over 60,000 software packages that can be installed with the Nix package manager (for Linux users):
https://github.com/NixOS/nixpkgs
RSS-proxy allows you to do create an RSS or ATOM feed of almost any website, just by analyzing just the static HTML structure:
https://github.com/damoeb/rss-proxy
Keyoxide allows you to link accounts on various online services and platforms together, prove they belong to you and establish an online identity:
https://keyoxide.org/