Any strong Mim deck will probably run Skithiryx, but another classic Mimeoplasm kill is to have him become a copy of Blackcleave Goblin with 13 +1/+1 counters from Death's Shadow
This legendary Centaur Druid costs , which isn't cheap but also isn't unreasonable
Damage Stackers: Instead of effects that multiply damage output, these add a set amount of extra damage on top of it (Torbran, Thane of Red Fell, Jaya, Venerated Firemage, Mechanized Warfare, etc.)
Since Reaper King is what turns Scarecrows into spot removal spells for any problem in play, it goes without saying that protecting it at all costs is critical once youre able to safely play it
Risk Versus Reward The first question I'd want to ask in any of these scenarios is what is the risk versus the reward here