Out of the Tombs

At the beginning of your upkeep, put two eon counters on Out of the Tombs, then mill cards equal to the number of eon counters on it.
If you would draw a card while your library has no cards in it, instead return a creature card from your graveyard to the battlefield. If you can't, you lose the game.

Mossborn Hydra

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
This creature enters with a +1/+1 counter on it.
Landfall — Whenever a land you control enters, double the number of +1/+1 counters on this creature.

Skull Prophet

{T}: Add {B} or {G}.
{T}: Mill two cards.

Rampaging Baloths

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

Weight Room

When you unlock this door, manifest dread, then put three +1/+1 counters on that creature.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Moldering Gym

When you unlock this door, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Moldering Gym // Weight Room

Exploration

You may play an additional land on each of your turns.

The Gitrog Monster

Deathtouch
At the beginning of your upkeep, sacrifice The Gitrog Monster unless you sacrifice a land.
You may play an additional land on each of your turns.
Whenever one or more land cards are put into your graveyard from anywhere, draw a card.

Tireless Provisioner

Landfall — Whenever a land you control enters, create a Food token or a Treasure token. (Food is an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life." Treasure is an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Bloodghast

Bloodghast can't block.
Bloodghast has haste as long as an opponent has 10 or less life.
Landfall — Whenever a land you control enters, you may return Bloodghast from your graveyard to the battlefield.

Stitcher's Supplier

When Stitcher's Supplier enters or dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Avenger of Zendikar

When Avenger of Zendikar enters, create a 0/1 green Plant creature token for each land you control.
Landfall — Whenever a land you control enters, you may put a +1/+1 counter on each Plant creature you control.

Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Conduit of Worlds

You may play lands from your graveyard.
{T}: Choose target nonland permanent card in your graveyard. If you haven't cast a spell this turn, you may cast that card. If you do, you can't cast additional spells this turn. Activate only as a sorcery.