Dark Ritual

Mountain

Unholy Strength

Enchant creature
Enchanted creature gets +2/+1.

Bog Imp

Flying (This creature can't be blocked except by creatures with flying or reach.)

Marsh Gas

All creatures get -2/-0 until end of turn.

Infernal Denizen

At the beginning of your upkeep, sacrifice two Swamps. If you can't, tap Infernal Denizen, and an opponent may gain control of a creature you control of their choice for as long as Infernal Denizen remains on the battlefield.
{T}: Gain control of target creature for as long as Infernal Denizen remains on the battlefield.

Wall of Bone

Defender (This creature can't attack.)
{B}: Regenerate Wall of Bone. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Demonic Consultation

Choose a card name. Exile the top six cards of your library, then reveal cards from the top of your library until you reveal a card with the chosen name. Put that card into your hand and exile all other cards revealed this way.

Junún Efreet

Flying
At the beginning of your upkeep, sacrifice Junún Efreet unless you pay {B}{B}.

El-Hajjâj

Whenever El-Hajjâj deals damage, you gain that much life.

Raise Dead

Return target creature card from your graveyard to your hand.

Cosmic Horror

First strike
At the beginning of your upkeep, destroy Cosmic Horror unless you pay {3}{B}{B}{B}. If Cosmic Horror is destroyed this way, it deals 7 damage to you.

Swamp

Will-o'-the-Wisp

Flying (This creature can't be blocked except by creatures with flying or reach.)
{B}: Regenerate Will-o'-the-Wisp. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Evil Eye of Orms-by-Gore

Non-Eye creatures you control can't attack.
Evil Eye of Orms-by-Gore can't be blocked except by Walls.

Lim-Dûl's Paladin

Trample
At the beginning of your upkeep, you may discard a card. If you don't, sacrifice Lim-Dûl's Paladin and draw a card.
Whenever Lim-Dûl's Paladin becomes blocked, it gets +6/+3 until end of turn.
Whenever Lim-Dûl's Paladin attacks and isn't blocked, it assigns no combat damage this turn and defending player loses 4 life.