Citadel of Pain

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.

Hickory Woodlot

Hickory Woodlot enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from Hickory Woodlot: Add {G}{G}. If there are no depletion counters on Hickory Woodlot, sacrifice it.

Scoria Cat

Scoria Cat gets +3/+3 as long as you control no untapped lands.

Flame Rift

Flame Rift deals 4 damage to each player.

Flowstone Overseer

{R}{R}: Target creature gets +1/-1 until end of turn.

Bifurcate

Search your library for a permanent card with the same name as target nontoken creature, put that card onto the battlefield, then shuffle.

Vintara Snapper

Vintara Snapper has shroud as long as you control no untapped lands. (It can't be the target of spells or abilities.)

Silt Crawler

When Silt Crawler enters, tap all lands you control.

Well of Discovery

At the beginning of your end step, if you control no untapped lands, draw a card.

Keldon Berserker

Whenever Keldon Berserker attacks, if you control no untapped lands, it gets +3/+0 until end of turn.

Avatar of Might

If an opponent controls at least four more creatures than you, this spell costs {6} less to cast.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Mountain

Forest

Nesting Wurm

Trample
When Nesting Wurm enters, you may search your library for up to three cards named Nesting Wurm, reveal them, put them into your hand, then shuffle.

Verdant Field

Enchant land
Enchanted land has "{T}: Target creature gets +1/+1 until end of turn."

Well of Life

At the beginning of your end step, if you control no untapped lands, you gain 2 life.

Barbed Field

Enchant land
Enchanted land has "{T}: This land deals 1 damage to any target."

Vine Trellis

Defender (This creature can't attack.)
{T}: Add {G}.

Task Mage Assembly

When there are no creatures on the battlefield, sacrifice Task Mage Assembly.
{2}: Task Mage Assembly deals 1 damage to target creature. Any player may activate this ability but only as a sorcery.

Avatar of Fury

If an opponent controls seven or more lands, this spell costs {6} less to cast.
Flying
{R}: Avatar of Fury gets +1/+0 until end of turn.

Spur Grappler

Spur Grappler gets +2/+1 as long as you control no untapped lands.

Two-Headed Dragon

Flying
Menace (This creature can't be blocked except by two or more creatures.)
Two-Headed Dragon can block an additional creature each combat.
{1}{R}: Two-Headed Dragon gets +2/+0 until end of turn.

Flameshot

You may discard a Mountain card rather than pay this spell's mana cost.
Flameshot deals 3 damage divided as you choose among one, two, or three target creatures.

Chimeric Idol

{0}: Tap all lands you control. Chimeric Idol becomes a 3/3 Turtle artifact creature until end of turn.

Sandstone Needle

Sandstone Needle enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from Sandstone Needle: Add {R}{R}. If there are no depletion counters on Sandstone Needle, sacrifice it.

Rushwood Grove

Rushwood Grove enters tapped.
{T}: Put a storage counter on Rushwood Grove.
{T}, Remove any number of storage counters from Rushwood Grove: Add {G} for each storage counter removed this way.