Best supported result
Bilbo, Thief in the Night
Spells you cast from anywhere other than your hand cost {1} less to cast. Whenever Bilbo attacks, you may cast an artifact, instant, or sorcery spell from your graveyard. If an instant or sorcery spell cast this way would be put into your graveyard, exile it instead.
Bilbo's discount rewards spells cast outside the hand, while attacking permits another artifact, instant, or sorcery from the graveyard. That makes both the mana curve and the graveyard contents relevant to evaluating a list. He still needs to survive until combat, and the recast spell still has a cost. The small recorded sample supports testing this role, not calling it a settled format staple.
Tournament evidence: Bilbo, Thief in the Night appeared in 2 Vintage decks across one event, with 4 total registered copies. 2 decks used it in the main deck and 0 used it in the sideboard. Example: adamwasmo in vintage league 2026 08 2511047 on 2026-08-25.