The new Izzet cards that care about instants and sorceries in exile and your graveyard Beacon Bolt, Crackling Drake, and Ral, Izzet Viceroy play nicely with Outpost Siege-style cards
It's not novel to grant a card some ability that's only usable once
Pendelhaven and The Seedcore provide some situational pump abilities
more precisely, its the artifact creature Metalworker
The Brothers' War (BRO) $487 The BRO Collector Boosters are an artifact-lovers heaven
You could ask: Are you going to attack me this turn? Do you have a counterspell in your hand? Are you able to win the game this turn? If I were to ask you if you concede the game, would your answer to that question be the same as the answer to this question? Spark Fiend is hilarious because its not entirely clear what the card does, why it does it, or how it does it