Okay so considering we have plugin iterators and command iterators there should be a way to know if a specific command belongs to a specific plugin. This data is already stored as functionality powers the built in sm cmds command.

However, parsing sm cmds has its own flaws (one being that commands names are cut off after 16 characters).

I propose a method to link commands to plugins is added to SourceMod.
I didn't find a way to do this without extensions so if this is already possible please enlighten me!

There are multiple ways in which this could be done.
One is to add a new API function that takes a command handle/name and gives you a plugin handle as returned by ReadPlugin(pluginIterator);.

Another method is to add a plugin num/id copyback to ReadCommandIterator.