Momo, Friendly Flier is a cheap flyer that reduces the cost of the first non-Lemur flying creature by
For example, if you control Muldrotha, the Gravetide ("During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard") and you cast a creature spell from your graveyard during your second main phase, you won't be able to cast another creature spell from your graveyard with Muldrotha's permission until after your next ending phase ends
You can have any number of them in your deck, so you could have several variations to use in a game rather than having to pick your favorite
I think the design space for a powerful deck is absolutely there, making the first face-down creature spell you cast each turn effectively free and making all face-down spells cantrip massively empowers the deck
Gruul to Be Kind Atarka, World Render | Illustration by Karl Kopinski And thats a wrap on our tour of the best Gruul cards