Sentinel

{0}: Change Sentinel's base toughness to 1 plus the power of target creature blocking or blocked by Sentinel. (This effect lasts indefinitely.)

Hammerheim

{T}: Add {R}.
{T}: Target creature loses all landwalk abilities until end of turn.

Gaea's Touch

{0}: You may put a basic Forest card from your hand onto the battlefield. Activate only as a sorcery and only once each turn.
Sacrifice Gaea's Touch: Add {G}{G}.

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

Wall of Ice

Land Leeches

Desert Twister

Marsh Viper

Whenever Marsh Viper deals damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.

Savaen Elves

{G}{G}, {T}: Destroy target Aura attached to a land.

Storm Seeker

Storm Seeker deals damage to target player equal to the number of cards in that player's hand.

Avoid Fate

Counter target instant or Aura spell that targets a permanent you control.

Lurker

Lurker can't be the target of spells unless it attacked or blocked this turn.

Forest

People of the Woods

People of the Woods's toughness is equal to the number of Forests you control.

Barbary Apes

Urza's Mine

{T}: Add {C}. If you control an Urza's Power-Plant and an Urza's Tower, add {C}{C} instead.

The Tabernacle at Pendrell Vale

All creatures have "At the beginning of your upkeep, destroy this creature unless you pay {1}."

The Rack

As The Rack enters, choose an opponent.
At the beginning of the chosen player's upkeep, The Rack deals X damage to that player, where X is 3 minus the number of cards in their hand.

Venom

Enchant creature
Whenever enchanted creature blocks or becomes blocked by a non-Wall creature, destroy the other creature at end of combat.

Spitting Slug

Whenever Spitting Slug blocks or becomes blocked, you may pay {1}{G}. If you do, Spitting Slug gains first strike until end of turn. Otherwise, each creature blocking or blocked by Spitting Slug gains first strike until end of turn.