-Jellyfin (i was astonished that this piece of software wasn’t mentioned before)
-SMPlayer (imho the best front end for MPV)
-shutdown command (i use it daily)
-Lutris
-Wine
-Piper (to manage keybings on the mouse with a gui) (is also the only one that I found that works with my G502, if you have an alternative please tell me, i want to check it out)
-ckb-next (for managing leds and keybindings for my keyboard)
-openRGB
Honorable mention:
Molly (the FOSS version, a privacy focused client for Signal)
Edit:
Almost forgot about QEMU+kvm for virtualization
I have the entire archive of RARGB (800Mb) and i am still seeding it. If you know how to use it, can still be useful.
Watch that shows how to use it and in one of the comments there is the link to download the archive