Helga, Skittish Seer

Whenever you cast a creature spell with mana value 4 or greater, you draw a card, gain 1 life, and put a +1/+1 counter on Helga.
{T}: Add X mana of any one color, where X is Helga's power. Spend this mana only to cast creature spells with mana value 4 or greater or creature spells with {X} in their mana costs.

Zidane, Tantalus Thief

When Zidane enters, gain control of target creature an opponent controls until end of turn. Untap it. It gains lifelink and haste until end of turn.
Whenever an opponent gains control of a permanent from you, you create a Treasure token.

Jodah, the Unifier

Legendary creatures you control get +X/+X, where X is the number of legendary creatures you control.
Whenever you cast a legendary spell from your hand, exile cards from the top of your library until you exile a legendary nonland card with lesser mana value. You may cast that card without paying its mana cost. Put the rest on the bottom of your library in a random order.

Ajani, Nacatl Avenger

+2: Put a +1/+1 counter on each Cat you control.
0: Create a 2/1 white Cat Warrior creature token. When you do, if you control a red permanent other than Ajani, he deals damage equal to the number of creatures you control to any target.
−4: Each opponent chooses an artifact, a creature, an enchantment, and a planeswalker from among the nonland permanents they control, then sacrifices the rest.

Ajani, Nacatl Pariah

When Ajani enters, create a 2/1 white Cat Warrior creature token.
Whenever one or more other Cats you control die, you may exile Ajani, then return him to the battlefield transformed under his owner's control.

Ajani, Nacatl Pariah // Ajani, Nacatl Avenger

Selvala, Explorer Returned

Parley — {T}: Each player reveals the top card of their library. For each nonland card revealed this way, add {G} and you gain 1 life. Then each player draws a card.

Phoenix, Warden of Fire

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Rising Flames — Phoenix deals 2 damage to each opponent.
III — Flames of Rebirth — Return any number of target creature cards with total mana value 6 or less from your graveyard to the battlefield. Exile Phoenix, then return it to the battlefield (front face up).
Flying, lifelink

Joshua, Phoenix's Dominant

When Joshua enters, discard up to two cards, then draw that many cards.
{3}{R}{W}, {T}: Exile Joshua, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery.