This card from strixhaven seems very powerful, but hasn't seen much discussion:

Creature — Human Shaman

Whenever Conspiracy Theorist attacks, you may pay {1} and discard a card. If you do, draw a card.

Whenever you discard one or more nonland cards, you may exile one of them from your graveyard. If you do, you may cast it this turn.
2/2
For example, it's very strong with stuff that relies on discard to be balanced like Lion's Eye Diamond or Gamble. I'm stuck wondering about something that combines Ridddlesmith as a looting engine with the conspiracy theorist and 0cc artifacts:


Conspiracy Theorist
Riddlesmith
Echo of Eons
Careful Study
Faithless Looting
Grapeshot

Chrome Mox
Mox Opal
Lotus Petal
Lion's Eye Diamond
Urza's Bauble
Mishra's Bauble

...