Where are NPC files?

I recently cleaned out my G-Mod folders by creating a new garrysmod/garrysmod folder. You know how it works. I moved the files I knew I still wanted from the old folder to the new one. In my old G-Mod, I had many old or broken NPCs that I didn’t use much, so I didn’t bring them to the new folder. However, when I start my cleaned out G-Mod, the icons and categories for the old NPCs are still there. What folder would I look in to delete the files for the NPCs and their categories in my NPC tab?