Suture Priest

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Trespasser's Curse

Enchant player
Whenever a creature enchanted player controls enters, that player loses 1 life and you gain 1 life.

Presence of Gond

Enchant creature
Enchanted creature has "{T}: Create a 1/1 green Elf Warrior creature token."

Essence Warden

Whenever another creature enters, you gain 1 life.

Midnight Guard

Whenever another creature enters, untap Midnight Guard.

Soul Warden

Soul's Attendant

Whenever another creature enters, you may gain 1 life.