msem-instigator

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

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.

Prevent all combat damage that Ancient Guardian would deal to or be dealt by creatures with no counters on them.

Trample
When Ancient Pillan enters, it fights up to one target creature an opponent controls.

When Ancient of the Glade enters, put a +1/+1 counter on each other creature you control.
{2}, Remove a +1/+1 counter from a creature you control: That creature gains indestructible until end of turn.

Defender
Andazir Elite can attack as though it didn't have defender as long as it's equipped.

Whenever Angeltouched Komodo attacks, scry 1.
Morph {1}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Activated abilities of sources you don't control can't be activated unless they're mana abilities.

When Anointed General enters, if you control a legendary creature, Anointed General deals 4 damage to target creature you don't control.

Flying, vigilance
Augmented — When Antigravity Agent enters, if you've spent {W}{U}{R}{B}{G} to cast spells this turn, distribute a flying counter and a vigilance counter among one or two creatures you control.

Colossal 4—{8} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {8} as a sorcery: Put four +1/+1 counters on it if it has none.)
Abilities you activate that aren't mana abilities cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Whenever Apex of Augmentation attacks, other creatures you control can't be blocked this turn.

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.

Prowess
When Arcane Dredger enters, return target instant or sorcery card from your graveyard to your hand.

If you casting a noncreature spell causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Cycling {2} ({2}, Discard this card: Draw a card.)

Flying, lifelink
{2}{W}{W}, Exile Archon of Sunrise from your graveyard: Create a token that's a copy of it, except it's an Aura enchantment with enchant creature and “Enchanted creature gets +4/+4 and has flying and lifelink.” Activate only as a sorcery.

Haste
Whenever Arisen Hunter attacks, target player loses 2 life and you gain 2 life.
If Arisen Hunter would die, exile it instead.

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.

Haste
Whenever Arpechian Tiger attacks, you may sacrifice a land. If you do, Arpechian Tiger deals 3 damage to target creature or planeswalker.

Once during each of your turns, when a card is put into a graveyard from anywhere, you may cast it. You may spend mana of any color to cast that spell.
When Arroyo, Infinitely Branching is put into your graveyard from anywhere, you may cast it.

Flying
At the beginning of your upkeep, you may create a token that is a copy of target Aura you control and attach it to target permanent or player it could enchant.
{2}, Sacrifice an Aura: Artiaburz gains indestructible and hexproof until end of turn.

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

Menace
Once during each of your turns, when you sacrifice a permanent, you may put a +1/+1 counter on Assimilated Runner.

Trample
Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Creatures you control gain vigilance until end of turn.
[Lore III] Remove all lore counters from Astral Leucrocota. You gain 4 life.