Ian Chesterton is a rare Legendary Creature — Human Scientist card from Doctor Who (WHO), collector number 341. Current market price: $0.43 (foil $0.61), TCGplayer market prices via Scryfall.
Science Teacher — Each Saga spell you cast has replicate. The replicate cost is equal to its mana cost. (When you cast that Saga, copy it for each time you paid its replicate cost. Copies of Saga spells become tokens.) Doctor's companion (You can have two commanders if the other is the Doctor.)