Storm of Souls

Return all creature cards from your graveyard to the battlefield. Each of them is a 1/1 Spirit with flying in addition to its other types. Exile Storm of Souls.

Soul Warden

Whenever another creature enters, you gain 1 life.

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.

Ashnod's Altar

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

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.

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Impact Tremors

Whenever a creature you control enters, Impact Tremors deals 1 damage to each opponent.

Isochron Scepter

Imprint — When Isochron Scepter enters, you may exile an instant card with mana value 2 or less from your hand.
{2}, {T}: You may copy the exiled card. If you do, you may cast the copy without paying its mana cost.

Otharri, Suns' Glory

Flying, lifelink, haste
Whenever Otharri, Suns' Glory attacks, you get an experience counter. Then create a 2/2 red Rebel creature token that's tapped and attacking for each experience counter you have.
{2}{R}{W}, Tap an untapped Rebel you control: Return Otharri from your graveyard to the battlefield tapped.