There is a list of several gems depending on ffi ( https://www.ruby-toolbox.com/projects/ffi https://www.ruby-toolbox.com/projects/ffi ), mostly system stuff:

There is a list of several gems depending on ffi ( https://www.ruby-toolbox.com/projects/ffi https://www.ruby-toolbox.com/projects/ffi ), mostly system stuff: Popular gems depending on ffi childprocess, rb-inotify, rb-kqueue, rb-fchange, ethon, spoon, minitest-chef-handler, win32-process, libnotify, nfqueue, net-ping, rubypython, sys-cpu, sys-uname, gssapi