Probably works best in Group Pain decks like Mogis, God of Slaughter and Rakdos, Lord of Riots, though those decks have access to Black so you already have great card draw
Theres a tough balancing act in finding the right number of black cards to make sure you can evoke Grief on the first turn, but playing weak cards just to add more black cards to the deck is not something I really want to do
Kiki-Jiki, Mirror Breaker [The Infinite Loop Engine] Kiki-Jiki, Mirror Breaker has been enabling absurd board states for years
Green is great at getting up to big mana, and having an 11-mana Craterhoof Behemoth in the command zone is a huge advantage for any creature deck
Features exclusive artwork ofThe Crystals Chosenby Kotetsu Kinoshita
If something is also wildly powerful in the 99, or simply unfun all around, were fine leaving it on the list, but power alone isnt a reason to list it as a Game Changer