Don't know if it is big or not, but Andy Brice's Perfect Table Plan is made with C++ and Qt, and IIRC, it runs on both Windows and macOS. It's been around for a

Don't know if it is big or not, but Andy Brice's Perfect Table Plan is made with C++ and Qt, and IIRC, it runs on both Windows and macOS. It's been around for a long time and sells fairly well, according to posts on his blog, successfulsoftware.net , which I have been reading for a while. The blog also has many good posts about desktop software product development and marketing. Also, he's pretty much a one-man show, except fr some things, which shows it can be done.