Anikthea, Hand of Erebos

Menace
Other enchantment creatures you control have menace.
Whenever Anikthea enters or attacks, exile up to one target non-Aura enchantment card from your graveyard. Create a token that's a copy of that card, except it's a 3/3 black Zombie creature in addition to its other types.

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.)

Eivor, Wolf-Kissed

Trample, haste
Whenever Eivor deals combat damage to a player, you mill that many cards. You may put a Saga card and/or a land card from among them onto the battlefield.

Tom Bombadil

As long as there are four or more lore counters among Sagas you control, Tom Bombadil has hexproof and indestructible.
Whenever the final chapter ability of a Saga you control resolves, reveal cards from the top of your library until you reveal a Saga card. Put that card onto the battlefield and the rest on the bottom of your library in a random order. This ability triggers only once each turn.

Garnet, Princess of Alexandria

Lifelink
Whenever Garnet attacks, you may remove a lore counter from each of any number of Sagas you control. Put a +1/+1 counter on Garnet for each lore counter removed this way.

Storyweave

Choose one —
• Put two +1/+1 counters on target creature you control.
• Put two lore counters on target Saga you control. The next time one or more enchantment creatures you control enter this turn, each enters with two additional +1/+1 counters on it.

Narci, Fable Singer

Lifelink
Whenever you sacrifice an enchantment, draw a card.
Whenever the final chapter ability of a Saga you control resolves, each opponent loses X life and you gain X life, where X is that Saga's mana value.

Clash of the Eikons

Choose one or more —
• Target creature you control fights target creature an opponent controls.
• Remove a lore counter from target Saga you control. (Removing lore counters doesn't cause chapter abilities to trigger.)
• Put a lore counter on target Saga you control.

Satsuki, the Living Lore

{T}: Put a lore counter on each Saga you control. Activate only as a sorcery.
When Satsuki 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.

Esper Terra

(As this Saga enters and after your draw step, add a lore counter.)
I, II, III — Create a token that's a copy of target nonlegendary enchantment you control. It gains haste. If it's a Saga, put up to three lore counters on it. Sacrifice it at the beginning of your next end step.
IV — Add {W}{W}, {U}{U}, {B}{B}, {R}{R}, and {G}{G}. Exile Esper Terra, then return it to the battlefield (front face up).
Flying

Terra, Magical Adept

When Terra enters, mill five cards. Put up to one enchantment card milled this way into your hand.
Trance — {4}{R}{G}, {T}: Exile Terra, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery.

Terra, Magical Adept // Esper Terra

Sigurd, Jarl of Ravensthorpe

Vigilance, trample, lifelink
Boast — {1}: Put a lore counter on target Saga you control or remove one from it. (Activate only if this creature attacked this turn and only once each turn.)
Whenever you put a lore counter on a Saga you control, put a +1/+1 counter on up to one other target creature.

Historian's Boon

Whenever this enchantment or another nontoken enchantment you control enters, create a 1/1 white Soldier creature token.
Whenever the final chapter ability of a Saga you control triggers, create a 4/4 white Angel creature token with flying and vigilance.

Rydia, Summoner of Mist

Landfall — Whenever a land you control enters, you may discard a card. If you do, draw a card.
Summon — {X}, {T}: Return target Saga card with mana value X from your graveyard to the battlefield with a finality counter on it. It gains haste until end of turn. Activate only as a sorcery.