Smells like Team Spirits

At the beginning of your upkeep, you may put a charge counter on Aether Vial.

{T}: You may put a creature card with converted mana cost equal to the number of charge counters on Aether Vial from your hand onto the battlefield.

As Cavern of Souls enters the battlefield, choose a creature type.

{T}: Add {C}.

{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

When Deputy of Detention enters the battlefield, exile target nonland permanent an opponent controls and all other nonland permanents that player controls with the same name as that permanent until Deputy of Detention leaves the battlefield.

Choose a creature type. Draw a card for each permanent you control of that type.

Flying

Other Spirit creatures you control get +1/+1 and have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Each player can't cast more than one spell each turn.

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle your library.

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.

Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

{T}: Another target creature you control gains protection from colorless or from the color of your choice until end of turn.

({T}: Add {W} or {U}.)

As Hallowed Fountain enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

{T}, Pay 1 life: Add {G} or {W}.

{1}, {T}, Sacrifice Horizon Canopy: Draw a card.

({T}: Add {U}.)

Flying

Creatures you control have "Whenever this creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability."

Flying

Whenever another Spirit enters the battlefield under your control, Mausoleum Wanderer gets +1/+1 until end of turn.

Sacrifice Mausoleum Wanderer: Counter target instant or sorcery spell unless its controller pays {X}, where X is Mausoleum Wanderer's power.

{T}: Add {C}.

{W}{U}, {T}, Exile a creature card from your graveyard: Create a 1/1 white Spirit creature token with flying.

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle their library.

You may have Phantasmal Image enter the battlefield as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

({T}: Add {W}.)

Flash

Flying

When Rattlechains enters the battlefield, target Spirit gains hexproof until end of turn.

You may cast Spirit spells as though they had flash.

When Rest in Peace enters the battlefield, exile all cards from all graveyards.

If a card or token would be put into a graveyard from anywhere, exile it instead.

Seachrome Coast enters the battlefield tapped unless you control two or fewer other lands.

{T}: Add {W} or {U}.

Flying

Sacrifice Selfless Spirit: Creatures you control gain indestructible until end of turn.

Flash

Flying

When Spell Queller enters the battlefield, exile target spell with converted mana cost 4 or less.

When Spell Queller leaves the battlefield, the exiled card's owner may cast that card without paying its mana cost.

Activated abilities of artifacts can't be activated.

Flying

Other Spirits you control get +1/+1.

This spell can't be countered.

Destroy all creatures.

First strike

Noncreature spells cost {1} more to cast.

Changeling (This card is every creature type.)

Whenever you or a permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.

{T}, Pay 1 life: Add {G} or {U}.

{1}, {T}, Sacrifice Waterlogged Grove: Draw a card.