Parasitic Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, its controller loses 2 life and you gain 2 life.

Sol Ring

Nirkana Revenant

Whenever you tap a Swamp for mana, add an additional {B}.
{B}: Nirkana Revenant gets +1/+1 until end of turn.

Treasure Nabber

Whenever an opponent taps an artifact for mana, gain control of that artifact until the end of your next turn.

Khârn the Betrayer

Berzerker — Khârn the Betrayer attacks or blocks each combat if able.
Sigil of Corruption — When you lose control of Khârn the Betrayer, draw two cards.
The Betrayer — If damage would be dealt to Khârn the Betrayer, prevent that damage and an opponent of your choice gains control of it.

Fell Mire

As Fell Mire enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.

Fell the Profane

Fell the Profane // Fell Mire

Sudden Spoiling

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Until end of turn, creatures target player controls lose all abilities and have base power and toughness 0/2.

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Shiny Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

The Sound of Drums

Enchant creature
Enchanted creature is goaded.
If enchanted creature would deal combat damage to a permanent or player, it deals double that damage instead.
{2}{R}: Return The Sound of Drums from your graveyard to your hand.

Xantcha, Sleeper Agent

Xantcha, Sleeper Agent enters under the control of an opponent of your choice.
Xantcha attacks each combat if able and can't attack its owner or planeswalkers its owner controls.
{3}: Xantcha's controller loses 2 life and you draw a card. Any player may activate this ability.

Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Ghoulish Impetus

Enchant creature
Enchanted creature gets +1/+1, has deathtouch, and is goaded.
When enchanted creature dies, return Ghoulish Impetus to the battlefield at the beginning of the next end step.

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.