There are numerous examples on freedesktop.org. Right near the top of the page you've got things like D-Bus and NetworkManager in there. Then there is FreeType

There are numerous examples on freedesktop.org. Right near the top of the page you've got things like D-Bus and NetworkManager in there. Then there is FreeType, Wayland, and so on. https://www.freedesktop.org/wiki/Software/ https://www.freedesktop.org/wiki/Software/