Jetbrains IntelliJ is a big contender, but I get along just fine in other, FOSS IDEs. I prefer GIMP to Photoshop, actually, but that may just be a case where I learned photo manipulation on GIMP and didn’t touch Photoshop until far later.

My final answer has to be in image processing/photo editing software. CaptureOne Pro is leagues ahead of anything FOSS I’ve ever tried. DarkTable, RawTherapee, ART, none of it can come close to comparing right now. No matter how much time I give it, I just… Can never make the transition. Which sucks, because CaptureOne is not available on Linux and it’s pretty well impossible to get it running. 🥲