More than once i've needed different Mutations when a breeder has become useless and would be better used as a fighter or ended up with a really good fighter dragon that i didn't realize would make a great breeder for my friends/clan
Maybe adding a rare/high time counter Mushroom/Findable of some sort that if you Eat/collect it'll give a 1 time use to Reset your mutations?
Like it's can have loads of possible spawn locations to make it harder to locate and maybe only 1-3 can be on the map at once with a 1-3 hour respawn timer? It could be an eatable mushroom or an object to collect and be stored in your pouch till it's used? (Dragon bound rather then account/server bound)
(I'm sorry if this has been suggested before, i'm not sure how to use the threads or how to search for related ones)