On the front, Cosima is a little hard to parse, but essentially, she works like so: at the beginning of your upkeep, you exile Cosima
(Choose any number of permanents and/or players, then give each another counter of each kind already there.) Creature - Druid Phyrexian Color tag templates(None) Annoyed Altisaur Reach, trample Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less
I think all the new summons are incredible in general not just in a Counters deck, I think Summon: Yojimbo and Summon: Valefor will be showing up in a bunch of future brews
Kutzil, Malamet Exemplar
No matter how many creatures you have, you cant block
There are even harder challenges available beyond the starting league, which are all ideal if you want to just play some Pokmon without any real stakes involved