Tegan Jovanka

Brave Heart — Whenever you attack, target attacking historic creature gets +1/+1 and gains indestructible until end of turn. (Artifacts, legendaries, and Sagas are historic.)
Doctor's companion (You can have two commanders if the other is the Doctor.)

Raff Capashen, Ship's Mage

Flash
Flying
You may cast historic spells as though they had flash. (Artifacts, legendaries, and Sagas are historic.)

Daring Archaeologist

When this creature enters, you may return target artifact card from your graveyard to your hand.
Whenever you cast a historic spell, put a +1/+1 counter on this creature. (Artifacts, legendaries, and Sagas are historic.)

Artificer's Assistant

Flying
Whenever you cast a historic spell, scry 1. (Artifacts, legendaries, and Sagas are historic. To scry 1, look at the top card of your library, then you may put that card on the bottom.)

Excalibur, Sword of Eden

This spell costs {X} less to cast, where X is the total mana value of historic permanents you control. (Artifacts, legendaries, and Sagas are historic.)
Equipped creature gets +10/+0 and has vigilance.
Equip legendary creature {2}

Ballad of the Black Flag

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I, II, III — Mill three cards. You may put a historic card from among them into your hand. (Artifacts, legendaries, and Sagas are historic.)
IV — Historic spells you cast this turn cost {2} less to cast.

Sarah Jane Smith

Whenever you cast a historic spell, investigate. This ability triggers only once each turn. (Artifacts, legendaries, and Sagas are historic. To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Doctor's companion (You can have two commanders if the other is the Doctor.)

Weatherlight

Flying
Whenever Weatherlight deals combat damage to a player, look at the top five cards of your library. You may reveal a historic card from among them and put it into your hand. Put the rest on the bottom of your library in a random order. (Artifacts, legendaries, and Sagas are historic.)
Crew 3

D'Avenant Trapper

Whenever you cast a historic spell, tap target creature an opponent controls. (Artifacts, legendaries, and Sagas are historic.)

The Capitoline Triad

Those Who Came Before — This spell costs {1} less to cast for each historic card in your graveyard. (Artifacts, legendaries, and Sagas are historic.)
Exile any number of historic cards from your graveyard with total mana value 30 or greater: You get an emblem with "Creatures you control have base power and toughness 9/9."

Elena, Turk Recruit

When Elena enters, return target non-Assassin historic card from your graveyard to your hand. (Artifacts, legendaries, and Sagas are historic.)
Whenever you cast a historic spell, put a +1/+1 counter on Elena.