Groundswell

Target creature gets +2/+2 until end of turn.
Landfall — If you had a land enter the battlefield under your control this turn, that creature gets +4/+4 until end of turn instead.

Guardian of Tazeem

Flying
Landfall — Whenever a land you control enters, tap target creature an opponent controls. If that land is an Island, that creature doesn't untap during its controller's next untap step.

Rampaging Baloths

Trample
Landfall — Whenever a land you control enters, create a 4/4 green Beast creature token.

Seer's Sundial

Landfall — Whenever a land you control enters, you may pay {2}. If you do, draw a card.

Khalni Heart Expedition

Landfall — Whenever a land you control enters, you may put a quest counter on this enchantment.
Remove three quest counters from this enchantment and sacrifice it: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Skyclave Squid

Defender
Landfall — Whenever a land you control enters, this creature can attack this turn as though it didn't have defender.

Kiora, the Crashing Wave

+1: Until your next turn, prevent all damage that would be dealt to and dealt by target permanent an opponent controls.
−1: Draw a card. You may play an additional land this turn.
−5: You get an emblem with "At the beginning of your end step, create a 9/9 blue Kraken creature token."

Likeness of the Seeker

Whenever this creature becomes blocked, untap up to three lands you control.

Azusa's Many Journeys

(As this Saga enters and after your draw step, add a lore counter.)
I — You may play an additional land this turn.
II — You gain 3 life.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Azusa's Many Journeys // Likeness of the Seeker

Architect of the Untamed

Landfall — Whenever a land you control enters, you get {E} (an energy counter).
Pay eight {E}: Create a 6/6 colorless Beast artifact creature token.

Calcite Snapper

Shroud (This creature can't be the target of spells or abilities.)
Landfall — Whenever a land you control enters, you may switch this creature's power and toughness until end of turn.

Explore

You may play an additional land this turn.
Draw a card.

Tatyova, Benthic Druid

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

Jaddi Offshoot

Defender
Landfall — Whenever a land you control enters, you gain 1 life.

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land you control enters, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.

Primeval Bounty

Whenever you cast a creature spell, create a 3/3 green Beast creature token.
Whenever you cast a noncreature spell, put three +1/+1 counters on target creature you control.
Landfall — Whenever a land you control enters, you gain 3 life.

Shoal Serpent

Defender
Landfall — Whenever a land you control enters, this creature loses defender until end of turn.

Kazandu Valley

Kazandu Mammoth

Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.