Jet Medallion, Bolass Citadel, draw spells, tutors, and black cards that lack colorless requirements in their mana costs tend to work best with Krrik, as they help you stretch your mana and card access into ridiculously explosive turns that can win you the game on the spot if your opponents dont have access to any interaction
Francisco, Fowl Marauder As a potential 2-mana partner commander, Francisco, Fowl Marauder joins the ranks of pirates that want to deal damage to your opponents like Malcolm, Keen-Eyed Navigator and Breeches, Brazen Plunderer
It can't be blocked by creatures of that color this turn
The major downside to this card is if an opponent has lots of creatures in play, like from a token-based deck, you could be stuck with no creatures in play yourself and an army from the token player