There's many tools like this, but I was inspired by VHS[0]. The thing is, VHS requires ffmpeg and chromium to create GIFs and videos, which is a nice approach, but it's too heavy for my taste.
Basically, I forked a simple terminal emulator[1] written in plain C and added commands to write output straight to a GIF file[2].
It's stil a WIP pet-project, but I believe it could be usefull for someone, for example, to create animated illustrations for documentation, blog posts and such.
[0] https://github.com/charmbracelet/vhs/