Fun fact, the .gif file format is kind of a joke in terms of features and performance. It only supports frame delay in hundredths of a second. So delay can be 1/100th of a second, meaning 100 FPS. Or you can increase it to 2/100ths of a second, meaning 50 FPS. But you can't do anything in between...
So: 100 fps, 50 fps, 33 fps, 25 fps, 20 fps, 16.67 fps, etc.
Imgflip uses mp4 video to display GIFs when viewed on Imgflip though, so they can be more precise.
Shouldn't be possible for a .gif file to have 18.5 fps, but the video output could be.