Satsuki, the Living Lore

{T}: Put a lore counter on each Saga you control. Activate only as a sorcery.
When Satsuki, the Living Lore dies, choose up to one —
• Return target Saga or enchantment creature you control to its owner's hand.
• Return target Saga card from your graveyard to your hand.

Ian Chesterton

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.)

Barbara Wright

History Teacher — Sagas you control have read ahead. (As a Saga enters, choose a chapter and start with that many lore counters. Skipped chapters don't trigger.)
Doctor's companion (You can have two commanders if the other is the Doctor.)