Captain Sisay

{T}: Search your library for a legendary card, reveal that card, put it into your hand, then shuffle.

Song of the Worldsoul

Whenever you cast a spell, populate. (Create a token that's a copy of a creature token you control.)

Havi, the All-Father

Havi has indestructible as long as there are four or more historic cards in your graveyard. (Artifacts, legendaries, and Sagas are historic.)
Sage Project — Whenever Havi or another legendary creature you control dies, return target legendary creature card with lesser mana value from your graveyard to the battlefield tapped.

Relic of Legends

{T}: Add one mana of any color.
Tap an untapped legendary creature you control: Add one mana of any color.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: This artifact deals 50 damage to any target.

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.

Annie Joins Up

When Annie Joins Up enters, it deals 5 damage to target creature or planeswalker an opponent controls.
If a triggered ability of a legendary creature you control triggers, that ability triggers an additional time.

Akroma's Memorial

Creatures you control have flying, first strike, vigilance, trample, haste, and protection from black and from red.

Sisterhood of Karn

This creature enters with a +1/+1 counter on it.
Paradox — Whenever you cast a spell from anywhere other than your hand, double the number of +1/+1 counters on this creature.

Kellan, the Kid

Flying, lifelink
Whenever you cast a spell from anywhere other than your hand, you may cast a permanent spell with equal or lesser mana value from your hand without paying its mana cost. If you don't, you may put a land card from your hand onto the battlefield.

Garruk, Caller of Beasts

+1: Reveal the top five cards of your library. Put all creature cards revealed this way into your hand and the rest on the bottom of your library in any order.
−3: You may put a green creature card from your hand onto the battlefield.
−7: You get an emblem with "Whenever you cast a creature spell, you may search your library for a creature card, put it onto the battlefield, then shuffle."

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Chulane, Teller of Tales

Vigilance
Whenever you cast a creature spell, draw a card, then you may put a land card from your hand onto the battlefield.
{3}, {T}: Return target creature you control to its owner's hand.