Overwhelming Stampede

Until end of turn, creatures you control gain trample and get +X/+X, where X is the greatest power among creatures you control.

Trail of Mystery

Whenever a face-down creature you control enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Whenever a permanent you control is turned face up, if it's a creature, it gets +2/+2 until end of turn.

Multani, Yavimaya's Avatar

Reach, trample
Multani, Yavimaya's Avatar gets +1/+1 for each land you control and each land card in your graveyard.
{1}{G}, Return two lands you control to their owner's hand: Return Multani from your graveyard to your hand.

Zimone's Hypothesis

You may put a +1/+1 counter on a creature. Then choose odd or even. Return each creature with power of the chosen quality to its owner's hand. (Zero is even.)

Tatyova, Benthic Druid

Landfall — Whenever a land you control enters, you gain 1 life and draw a card.

Aesi, Tyrant of Gyre Strait

You may play an additional land on each of your turns.
Landfall — Whenever a land you control enters, you may draw a card.

Simic Signet

Koma, World-Eater

This spell can't be countered.
Trample, ward {4}
Whenever Koma deals combat damage to a player, create four 3/3 blue Serpent creature tokens named Koma's Coil.

Curator Beastie

Reach
Colorless creatures you control enter with two additional +1/+1 counters on them.
Whenever Curator Beastie enters or attacks, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Zimone, Mystery Unraveler

Landfall — Whenever a land you control enters, manifest dread if this is the first time this ability has resolved this turn. Otherwise, you may turn a permanent you control face up. (To manifest dread, look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Scroll of Fate

{T}: Manifest a card from your hand. (Put that card onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Zimone, Quandrix Prodigy

{1}, {T}: You may put a land card from your hand onto the battlefield tapped.
{4}, {T}: Draw a card. If you control eight or more lands, draw two cards instead.

Eureka Moment

Draw two cards. You may put a land card from your hand onto the battlefield.

Koma, Cosmos Serpent

This spell can't be countered.
At the beginning of each upkeep, create a 3/3 blue Serpent creature token named Koma's Coil.
Sacrifice another Serpent: Choose one —
• Tap target permanent. Its activated abilities can't be activated this turn.
• Koma, Cosmos Serpent gains indestructible until end of turn.

Thousand Winds

Flying
Morph {5}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Thousand Winds is turned face up, return all other tapped creatures to their owners' hands.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Sol Ring

Coiling Oracle

When Coiling Oracle enters, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put that card into your hand.

Xolatoyac, the Smiling Flood

Whenever Xolatoyac, the Smiling Flood enters or attacks, put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it.
At the beginning of your end step, untap each permanent you control with a counter on it.