msem-instigator

Creatures you don't control get -1/-1.
Mirage {1}{B} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Antu, Sun Spirit can't attack or block unless you control ten or more permanents.
As long as it's your turn, other creatures you control get +X/+0 and have haste, where X is the amount of life you've gained this turn.
When Antu dies or is put into exile from the battlefield, you may put him into his owner's library third from the top.

Vigilance, trample
Whenever another Horror you control enters, choose one —
• Destroy target artifact or enchantment.
• You gain 4 life.
• Apex Abomination fights another target creature.

Apothecary's Gift deals 5 damage to target creature or planeswalker. You gain life equal to the excess damage dealt this way.

At the beginning of your end step, put an encroachment counter on Approach of Old Lovi, then it deals X damage to any target and you gain X life, where X is the number of encroachment counters on Approach of Old Lovi.

Flash
Flying
As long as an opponent controls more creatures than you, Arbiter of the Scales gets +2/+2 and has first strike and lifelink.

Trample
When Arborback Stomper enters, you gain 5 life.

Whenever you cast an instant or sorcery spell, you may pay {1}. If you do, choose one—
• Draw a card, then discard a card.
• Tap target creature.
• Target creature gains flying until end of turn.
• Target player mills two cards.

Flying
When Arcanum Owl enters, you may return target instant or sorcery card from your graveyard to your hand.

Create three 2/2 green Wolf creature tokens.

Flying
Whenever a creature you control phases in, it gains flying until end of turn.

Trample
When Arpechian Bellowers enters, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Search your library for a green creature card, reveal it, put it into your hand, then shuffle.

Trample
When Arpechian Yatte enters, put a +1/+1 counter on each other creature you control.
Whenever another creature you control enters, put a +1/+1 counter on Arpechian Yatte.

If a player would draw a card, instead that player may put a card they own exiled with Arroyo, the Bound into their hand.
{3}: Search target player's library for a card and exile it face down, then that player shuffles. They may look at that card for as long as it remains exiled.

Draw two cards. You may cast an instant or sorcery spell with mana value X or less from your hand without paying its mana cost, where X is the number of cards in your hand.

When Artian, Phyrexian Architect enters, search your library for a land card, put it onto the battlefield, then shuffle.
At the beginning of your upkeep, put a corruption counter on a land you control. Then create a 1/1 colorless Phyrexian artifact creature token for each land you control with a corruption counter on it.

Creatures you control get +2/+2.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

First mate — Each land card in your starting deck has a different name. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Lifelink, vigilance
Asabeth of the Intrepid's power and toughness are each equal to the number of lands you control.

This spell costs {3} less to cast if you control three or more enchantments.
Trample

Trample
When Ashka Ritualist enters or whenever you cast a spell, if {R}{W} was spent to cast it, create two 1/1 red and green Warrior creature tokens. Put a +1/+1 counter on Ashka Ritualist.

Haste
Augmented — At the beginning of combat on your turn, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, gain control of target nonland permanent until end of turn. Untap it. It gains haste until end of turn.

You may put a creature card from your hand onto the battlefield. That creature gains haste until end of turn. Sacrifice that creature at the beginning of the next end step unless you pay its mana cost reduced by up to {3}{R}{R}.

Flying
When Augur of Bleak Horizons enters, you gain 3 life and you mill three cards.

Enchant creature
When Aura of Leadership enters, create four 1/1 white Human Soldier creature tokens.
Enchanted creature gets +2/+2.

This spell can't be countered.
Hexproof