The Beta box topper is fairly tame, including a foil Sorcery and rubble token as well as a handful of tokens (foot soldiers, frogs, etc)
Class abilities can be static, activated, or triggered abilities
Mill is a difficult strategy to pull off, as the odds are stacked against you from the beginning, so these cards and strategies will hopefully get you flipping your opponents decks upside down in no time
But you don't have to be so literal, either, only looking at cards with actual Hellbent
Peregrine Drake Peregrine Drakes enters ability makes it a free 2/3, which is cute, but this blue creature gained infamy for all the infinite combos it enables with cards like Deadeye Navigator that repeatedly flicker it for less than 5 mana
Penny sleeves and team bags are the absolute baseline protections