If youre looking for effects that add 1-time bursts of mana to your mana pool like Dark Ritual and Cabal Ritual, black and red are absolutely the colors to go to for them
Nyx-Fleece Ram works so well against those decks because: It comes out early and is a body large enough to block the majority of ground-based 1- to 3-drops without dying
Decklist: 1 Kinnan, Bonder Prodigy
This cheaper mana cost allows for interesting decision-making around whether you want to efficiently use your mana at the cost of another card, or be more card advantage conscious by holding up three mana instead
It's printed on a thicker cardstock and is not a tournament-legal Magic card, but it still allows you to show off your commander and carry it inside the deck box
This Magic set wants to capture the feeling of something dreadful being out there, unseen, creeping up on the survivors