Swamp

Grim Guardian

Constellation — Whenever Grim Guardian or another enchantment enters the battlefield under your control, each opponent loses 1 life.

Vampire Sovereign

Flying
When Vampire Sovereign enters the battlefield, target opponent loses 3 life and you gain 3 life.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Goliath Paladin

Vigilance
When Goliath Paladin enters the battlefield, you take the initiative.

Plains

Thraben Inspector

When Thraben Inspector enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Contaminated Ground

Enchant land
Enchanted land is a Swamp.
Whenever enchanted land becomes tapped, its controller loses 2 life.

Orzhov Basilica

Orzhov Basilica enters the battlefield tapped.
When Orzhov Basilica enters the battlefield, return a land you control to its owner's hand.
{T}: Add {W}{B}.

Ethereal Armor

Enchant creature
Enchanted creature gets +1/+1 for each enchantment you control and has first strike.

Hopeless Nightmare

When Hopeless Nightmare enters the battlefield, each opponent discards a card and loses 2 life.
When Hopeless Nightmare is put into a graveyard from the battlefield, scry 2.
{2}{B}: Sacrifice Hopeless Nightmare.

Spirited Companion

When Spirited Companion enters the battlefield, draw a card.

Journey to Nowhere

When Journey to Nowhere enters the battlefield, exile target creature.
When Journey to Nowhere leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Kor Skyfisher

Flying
When Kor Skyfisher enters the battlefield, return a permanent you control to its owner's hand.

Auramancer

When Auramancer enters the battlefield, you may return target enchantment card from your graveyard to your hand.

Oblivion Ring

When Oblivion Ring enters the battlefield, exile another target nonland permanent.
When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.