Darien, King of Kjeldor

Whenever you're dealt damage, you may create that many 1/1 white Soldier creature tokens.

Mana Echoes

Whenever a creature enters, you may add an amount of {C} equal to the number of creatures you control that share a creature type with it.

{T}: Heartless Hidetsugu deals damage to each player equal to half that player's life total, rounded down.

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Whenever a creature enters, that creature's controller may have it deal damage equal to its power to any target of their choice.

Whenever a creature you control enters, it deals damage equal to its power to any target.

{T}, Sacrifice a creature: Blasting Station deals 1 damage to any target.
Whenever a creature enters, you may untap Blasting Station.

Whenever a player casts a spell with mana value 3 or less, Eidolon of the Great Revel deals 2 damage to that player.