Ultimecia, Temporal Threat

When Ultimecia enters, tap all creatures your opponents control.
Whenever a creature you control deals combat damage to a player, draw a card.

Shiva, Warden of Ice

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Mesmerize — Target creature can't be blocked this turn.
III — Cold Snap — Tap all lands your opponents control. Exile Shiva, then return it to the battlefield (front face up).

Jill, Shiva's Dominant

When Jill enters, return up to one other target nonland permanent to its owner's hand.
{3}{U}{U}, {T}: Exile Jill, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery.

Jill, Shiva's Dominant // Shiva, Warden of Ice

Venser, Shaper Savant

Flash (You may cast this spell any time you could cast an instant.)
When Venser enters, return target spell or permanent to its owner's hand.

Quistis Trepe

Blue Magic — When Quistis Trepe enters, you may cast target instant or sorcery card from a graveyard, and mana of any type can be spent to cast that spell. If that spell would be put into a graveyard, exile it instead.

The Destined Thief

The Destined Thief can't be blocked.
{U}, {T}: Another target creature you control can't be blocked this turn.
Whenever one or more creatures you control deal combat damage to one or more players, draw a card, then discard a card. If you have a full party, instead draw three cards.

Gogo, Master of Mimicry

{X}{X}, {T}: Copy target activated or triggered ability you control X times. You may choose new targets for the copies. This ability can't be copied and X can't be 0. (Mana abilities can't be targeted.)

Lulu, Stern Guardian

Whenever an opponent attacks you, choose target creature attacking you. Put a stun counter on that creature.
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Hraesvelgr of the First Brood

Flying, vigilance, ward {2}
Shiva's Aid — When Hraesvelgr enters and whenever you cast a noncreature spell, target creature gets +1/+0 until end of turn and can't be blocked this turn.

O'aka, Traveling Merchant

{T}, Remove a counter from a nonland permanent you control: Draw a card.

Matoya, Archon Elder

Whenever you scry or surveil, draw a card. (Draw after you scry or surveil.)

Teferi, Mage of Zhalfir

Flash
Creature cards you own that aren't on the battlefield have flash.
Each opponent can cast spells only any time they could cast a sorcery.

Rikku, Resourceful Guardian

Whenever you put one or more counters on a creature, until end of turn, that creature can't be blocked by creatures your opponents control.
Steal — {1}, {T}: Move a counter from target creature an opponent controls onto target creature you control. Activate only as a sorcery.

Hermes, Overseer of Elpis

Whenever you cast a noncreature spell, create a 1/1 blue Bird creature token with flying and vigilance.
Whenever you attack with one or more Birds, scry 2.

Urza, Lord High Artificer

When Urza enters, create a 0/0 colorless Construct artifact creature token with "This token gets +1/+1 for each artifact you control."
Tap an untapped artifact you control: Add {U}.
{5}: Shuffle your library, then exile the top card. Until end of turn, you may play that card without paying its mana cost.

Edgar, King of Figaro

When Edgar enters, draw a card for each artifact you control.
Two-Headed Coin — The first time you flip one or more coins each turn, those coins come up heads and you win those flips.

Ultros, Obnoxious Octopus

Whenever you cast a noncreature spell, if at least four mana was spent to cast it, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you cast a noncreature spell, if at least eight mana was spent to cast it, put eight +1/+1 counters on Ultros.