Ublock-origin with Firefox, Audacity, Batch Photo Resizer, calibre, cardflow, Diffraction, Ejimo and Ultra Character Map (try finding emojis without them), Libre Office, Paprika Recipe Manager, Samurai Safe, SeaMonkey (who else edits HTML?) GIMP, Darktable, RawTherapee, Super Photo Upscaler, Sublime Text, VLC, Clearview (and why isn't epub supported natively?), PhotoSync (share photos with all platforms), GhostText for editing browser text areas with Sublime Text or other. (life-saver)

Ones I actually use.