If youre just starting out in MTG Arena or MTG, keep your creatures and spells cheap and just go for all-out aggression
Sacrificing things to Greyfax is just one option, you could throw them to Commissar Serverina Raine instead for life and cards, or to The Golden Throne for mana
His -5 gives you an emblem that makes it so you can tap your Mountains to deal one damage to any target
That opens the door to devastating setups: You can tutor Necropotence for absurd card draw or assemble game-ending combos like Rest in Peace plus Helm of Obedience
For each opponent who does, you gain protection from that player until your next turn." (You can't be targeted, dealt damage, or enchanted by anything controlled by that player.) Protection from a player means that you have protection from each object controlled by that player
Bannings only happen every few months, and the last time cards were considered for banning was on July 2024, which had no cards banned or unbanned at that time