@stux My favorites:

GIMP (Photo Editing)
https://www.gimp.org/

Audacity (Professional audio editing software)
https://www.audacityteam.org/

KDENLive (Video editor w/ good simple video effects)
https://kdenlive.org/en/

Shotcut (Another neat video editor, slightly unstable at times)
https://shotcut.org/

Minetest (A #FOSS Minecraft clone)
https://www.minetest.net/