Comment by WesolyKubeczek

Except stuff in /Library/Application Support. Oh, and /Library/Extensions. Oh, and /Library/DriverExtensions. Oh, and /Library/LaunchAgents. And /Library/LaunchDaemons. Also /Library/Perl (this is Apple-provided) and /Library/TeX (this is not, this is MacTeX). And /Library/Developer.

Also, the dread of "removal instructions" that include stuff like "go through these directories and delete things that look like they belong to this software".