With thousands upon thousands of Pokmon cards and would-be trainers each having their own preferences for types, Pokmon and abilities, it's hard to pin down what makes the best Pokmon cards
Hybrid Mana Not necessarily a mechanic but hybrid mana makes a return in Tarkir: Dragonstorm
Having such a tiny core engine means people can splash it with other great cards and get over, but running the deck pure isnt a bad idea either so long as a player is willing to run the best Infinitrack monster, Infinitrack Fortress Megaclops and Divine Arsenal AA-ZEUS as boss monsters
If that event was a team event, there may be more than one
Thassas Oracle Perhaps the most infamous merfolk in cEDH and one of blue's best ETB cards, Thassa's Oracle has made a name for itself alongside various combo pieces like Inverter of Truth, Demonic Consultation, and Hermit Druid that empty your library for an easy win