There are only a handful of Commander decks where card draw is a key mechanic rather than simply an advantage and a way to get slightly ahead
What if a Spell Somehow Has Double Convoke
This is chaotic, as you can get practically any spell from your deck, be it one of the biggest, baddest of the Eldrazi titans or a Llanowar Elves
Once its Night, anytime you cast a Double-Faced Card that has Daybound/Nightbound, it will enter the battlefield Nightbound
Beyond just being rare, thanks in part to the limited-run printing of Secret Lair drops, and their Bonus Cards, Mana Vault is insanely strong
Quarum Trench Gnomes ability is extremely topical, but also annoying to the point of getting the right opponent to ragequit