I want to start off by saying this is a datapack. Please download this and do NOT unzip it, and put it in the proper folder. This is not a mod OR plugin.
This datapack prevents all NPCs from spawning in 1.16.5 version of Pixelmon. This also allows villagers to spawn, but if you do not want that, you are free to edit this pack on your own.
I had help from someone named mattiqiuu, who does a lot of datapack related stuff. Here is a link to his fiverr if you are interested in his services.
If you have any questions my discord is Plazma#1768. I am always open to questions!
I also have a Pixelmon server of my own, you can play on it here - https://discord.gg/sjPr5reFKp
The NPC Removal Team
