What Foes, Mid-game, Drop Mutation SO's?

[EonRecoil]

I can't seem to get Mutation drops from foes in my 20s.  I know early game. Vahz, and Lost drop Mutation enhancements.  But they don't show up in the level 20 missions hardly at all.  What other foes drop Mutation SO's?

[SeraphimKensai]

https://strategywiki.org/wiki/City_of_Heroes/Enhancements can give you some insight, but otherwise, I would recommend if you can afford it, you can buy/create and slot in lvl 25 generic IO's, they are relatively cheap considering IO's and will last you until you hit lvl 50 allowing you to bank more influence and buy lvl 50 generics or start adding set pieces.