msem-instigator

At the beginning of your upkeep, choose two different basic land types. Create a colorless land token that's the chosen types.
At the beginning of your end step, sacrifice a land.

At the beginning of your end step, draw a card.
Whenever a creature deals combat damage to you, that creature's controller gains control of Ambition's Crown.

Bleed {1}{U} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Draw two cards.

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, return target creature card with mana value 3 or less from your graveyard to the battlefield.

Ambitious Ostrich has flying as long as you control a storied permanent. (Enchantments and legendary permanents are storied.)

Flash
When Ambush Gharial enters, it fights up to one target creature. If that creature would die this turn, exile it instead.

Reach
When Ambush Predator enters, you may return target Horror creature card from your graveyard to your hand.
When Ambush Predator dies, exile it and create a 3/2 green Horror creature token.

Flash (You may cast this spell any time you could cast an instant.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Trample
As long as it's an opponent's turn, Ambushing Alligator is a blue Bird with base power and toughness 1/1 and has flying and hexproof.

[+2]: Add {R}{R}. Until end of turn, red mana doesn't empty as steps and phases end, and creatures you control gain “{R}: This creature gets +1/+0 until end of turn.”
[–3]: You may cast a monocolored red spell with mana value 6 or less from your hand without paying its mana cost.
[–6]: You may pay any amount of {R}. When you do, Amelie Mayn deals that much damage to each of up to that many different targets.

Lifelink
At the beginning of each end step, if you gained life this turn, you may pay {W/B}. If you do, create a 1/1 white Spirit creature token with flying.

Flying
When Ameret's Favored enters, you gain 3 life.

At the beginning of combat on your turn, if there are seven or more loyalty counters on Ameret, they become a 5/5 Angel creature with flying and indestructible until end of turn.
[+1]: Create a 1/1 red and white Cleric creature token with lifelink and haste.
[–X]: Ameret deals X damage to any target. You gain X life.

As long as it's your turn, Ameret is a 4/4 Angel creature with flying, haste, indestructible, and “Whenever Ameret attacks, attach any number of Equipment you control to them.”
[+2]: Create two 1/1 red and white Cleric creature tokens with lifelink.
[–3]: Ameret deals 4 damage to target creature or planeswalker. You gain 4 life.
[–4]: For each creature you control, create a Weapon token and attach it to that creature. (It's an Equipment artifact with equip {2} and “Equipped creature gets +1/+1.”)

Flying
Soldiers and Knights you control get +1/+1.

Amid Flames deals 5 damage to target creature or planeswalker.
You may sacrifice a land. If you do, draw a card.

When Aminatou's Adherent enters, judge target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)
Whenever you condemn a creature, creatures you control gain menace until end of turn.

Create three 1/1 black Insect creature tokens with flying, then judge each of them. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

[+1]: Scry 2. Create a 1/1 black Insect creature token with flying.
[–2]: Judge each creature you control.
[–8]: For each card type, search your library and graveyard for a card of that type and exile it, then shuffle. You may play any number of cards exiled this way without paying their mana costs.

When Amira, Grand Inventor enters, create a 1/1 colorless Construct Artificer artifact creature token. If you control six or more artifacts, create a 6/6 colorless Golem artifact creature token instead.
Artifact tokens you control have all activated abilities of other artifact tokens you control.

Amleth, Royal Claimant can't be blocked by creatures with power 3 or less.
At the beginning of your end step, if you control three or more tapped creatures, create a 4/4 white Angel creature token with flying and vigilance. Otherwise, create a 1/1 white Soldier creature token.

Ammbradu Goliath gets -4/-4 for each card in your hand.

Ammbradu Parasite gets +1/+1 as long as you control a Forest.
{4}{G}: Target creature must be blocked this turn if able.

Bleed {R} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Amongst the Flames deals 2 damage to each creature.

Reach, vigilance
When Amorphous Tyrant enters, another target creature you control deals damage equal to its power to target creature or planeswalker you don't control.
Evoke {G} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)