Big mana colorless decks have always been players in Legacy, as Ancient Tomb and City of Traitors are powerful engines
The deck is reliant on specific cards so I'm running a much higher than average amount of tutors: Trinket Mage to find our busted mana rocks, Tribute Mage to find Throne of Geth simply the best card in the 99, Solve the Equation and Mystical Teachings to find our poison cards, and Ringsight to find any black/blue card with Venser out, plus gives him skulk to get around blockers
[1] You can spend money on the game if youd like, but if you keep playing for free you should be able to unlock enough cards to build a deck you like
But the OG Grinch also needed to do a lot of preparation in order to successfully steal Christmas
In cEDH, cards like Grim Monolith are often used in infinite combos
Theme boosters are perfect for players looking to expand their collection with a specific strategy in mind