There is a systemless supplement called The Metamorphica (https://www.drivethrurpg.com/product/115703/The-Metamorphica-Classic-Edition). It is great. I love it. Full of random tables for mutations such mental, physical, psionic, supernatural, etc. mutations as well as descriptions of them. There are sections on using mutations for different genres and there are even a collection of different mutated NPCs and monsters.
In the Planescape 5e campaign I DM we have a character who recently got trapped in Limbo and now he has a very short temper (Behavioral Mutation) and the ability to duplicate (like Multiple Man but limited to one copy). It gives him a boost in power but it is thematic and a lot of fun. There is also risk involved. Does he sacrifice his duplicate so his party can escape, or does he save it for later and risk his party’s safety and survival.
I have an idea to run an X-Men Campaign where everyone randomly generates their Mutant using the random tables to create their characters. The idea being the Mutants in X-Men didn’t get to choose their Mutations, unless you count Mister Sinister ¯\_(ツ)_/¯, so neither will the players. I think it could be fun.
But you could use The Metamorphica to create (and even play) Post Apocalyptic Irradiated Wastelanders, Chaos Warped Demonic Abominations, Body Horror Experimentation Victims, Super Soldiers, Superheroes, Bizarre Alien Lifeforms, Formless Dream Entities, Eldritch Monstrosities, or beings trapped in Limbo.
Mutations range from Anthropomorphic Animal to Hunchback, from Double Jointed to Diabetic, from Genetic Memory to Dyslexia, from Magnetic Control to Cause Insanity, from Animated Tattoos to Cannot Cross Running Water, and so many more.
There is so much you can do with this product. I thoroughly enjoyed it and highly recommend it. This review is not sponsored, I did not receive money from them or anyone else to review this. I simply gotta spread the love of an awesome product. 5 out of 5 stars.
The Metamorphica: https://www.drivethrurpg.com/product/115703/The-Metamorphica-Classic-Edition
