I use an HDL simulator which creates lots of large (hundred MB) binaries with seemingly random names -- these files do not have an extension. I'd like to keep these out of my Git repo.
I read on .gitignore without binary files a few techniques for ignoring files without extensions, but they're all pretty narrow in scope.
One of the challenges I face is that every time I run the simulator it generates new and randomly named binary outputs (e.g. it's unrealistic to manually add each one of these files to the ignore file).