Swamp

Have

Carrion Ants

{1}: Carrion Ants gets +1/+1 until end of turn.

Sengir Vampire

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature dealt damage by Sengir Vampire this turn dies, put a +1/+1 counter on Sengir Vampire.

Triskelion

Triskelion enters with three +1/+1 counters on it.
Remove a +1/+1 counter from Triskelion: It deals 1 damage to any target.

Dragon Engine

{2}: Dragon Engine gets +1/+0 until end of turn.

Nettling Imp

{T}: Choose target non-Wall creature the active player has controlled continuously since the beginning of the turn. That creature attacks this turn if able. Destroy it at the beginning of the next end step if it didn't attack this turn. Activate only during an opponent's turn, before attackers are declared.

Urza's Tower

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

Urza's Mine

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

Hell's Caretaker

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

Relic Barrier

Xenic Poltergeist

{T}: Until your next upkeep, target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.

Greed

Ashes to Ashes

Exile two target nonartifact creatures. Ashes to Ashes deals 5 damage to you.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Demonic Hordes

{T}: Destroy target land.
At the beginning of your upkeep, unless you pay {B}{B}{B}, tap Demonic Hordes and sacrifice a land of an opponent's choice.

Royal Assassin

Phyrexian Gremlins

You may choose not to untap Phyrexian Gremlins during your untap step.
{T}: Tap target artifact. It doesn't untap during its controller's untap step for as long as Phyrexian Gremlins remains tapped.

Winter Orb

As long as Winter Orb is untapped, players can't untap more than one land during their untap steps.

Urborg

{T}: Add {B}.
{T}: Target creature loses first strike or swampwalk until end of turn.

Urza's Power Plant

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

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.