Mizzix of the Izmagnus I know, don't play him
This has the bonus of being game-over for infinite elves decks
For example, if Nethergoyf is in your library, its toughness is determined by the ability "Nethergoyf's power is equal to the number of card types among cards in your graveyard and its toughness is equal to that number plus 1." If your graveyard consists of an artifact card, a creature card, and an instant card, you won't be able to find Nethergoyf with Recruiter of the Guard since Nethergoyf's toughness will be 4
Each booster includes one to five rares or higher, three to six uncommons, five to eight commons, and one land card
you need your instants and sorceries to be cheap, because a cantripping Slime Against Humanity just isnt worth four or five mana, and conversely, since youre actually casting two spells, a single cost-reducer actually saves you two mana instead of just one