I've been using this tool for a while. It's great for when you're familiar with a command but would prefer a list of common examples instead of a detailed man page for whatever reason.

Resizing an image with imagemagick's convert utility is extremely common, but invoking the binary with -? or bringing up the man page will get you way more information than you're actually looking for, whereas the cheatsheet[1] has exactly what you need right there.

[1]: https://github.com/cheat/cheatsheets/blob/master/convert