msem-instigator

At the beginning of combat on your turn, creatures you control gain your choice of trample, menace, haste, or +1/+0 until end of turn.

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
When this creature dies, it deals X damage to target player or planeswalker, where X is the number of cards and tokens merged with it.

Colossal 3—{4}{R}{G} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {4}{R}{G} as a sorcery: Put three +1/+1 counters on it if it has none.)
Each creature you control with a counter on it can't be blocked by more than one creature.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Whenever a creature you control attacks alone, target creature an opponent controls blocks this turn if able.

Flying
As long as you control an equipped creature, Guide of Heroes gets +1/+1 and has first strike.
As long as you control an enchanted creature, Guide of Heroes gets +1/+1 and has vigilance.

Haste
Gyr, Awoken World has all activated abilities of other lands you control.
As long as Gyr, Awoken World is on the battlefield or in your graveyard, it's a land in addition to its other types.

Each nontoken land you control has all activated abilities of each other land on the battlefield.
When Idyll leaves the battlefield, until the end of your next turn, you gain “Each nontoken land you control has all activated abilities of each other land on the battlefield.”

Creatures you control have “Whenever this creature attacks, put a +1/+1 counter on target creature with lesser power.”
At the beginning of each end step, if there are five or more +1/+1 counters among creatures you control, destroy up to one target artifact or enchantment.

Other Wolves and Werewolves you control have haste.
Leyran Hunting Pack gets +1/+1 for each non-Human Werewolf you control.

When Lionfrill Hunter enters or when you cycle it, put X +1/+1 counters on another target creature you control, where X is the number of cards with a cycling ability in your graveyard.
Cycling {3}{R}{G} ({3}{R}{G}, Discard this card: Draw a card.)

Whenever you activate an ability of a creature that isn't a mana ability, Moranai Tracker gets +1/+1 until end of turn.

Whenever you tap a land for mana, add one mana of any type that land produced.
Whenever you cast a spell with mana value greater than the number of lands you control, sacrifice a land.

Vigilance, trample
{5}{R}{G}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)

First strike, trample
Whenever Regal Coralhorn deals combat damage to a player or planeswalker, return target card with a cycling ability from your graveyard to your hand.
Cycling {2} ({2}, Discard this card: Draw a card.)

Trample
Whenever a noncreature permanent is put into a graveyard from the battlefield, put a +1/+1 counter on Ruinous Naga.

Trample
Whenever Simian Sentinel attacks, it gets +X/+0 until end of turn, where X is the number of lore counters on Sagas you control.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Vigilance, trample
{G}{W}: Demon — Abwad Kahroba gains “At the beginning of combat on your turn, you may put a +1/+1 counter on another target creature.”
{X}{G}{W}: Elder — Create X 2/1 black Horror creature tokens. You gain X life.

Whenever one or more counters are put on a permanent you control for the first time each turn, create that many 1/1 green Squirrel creature tokens.
{1}{G}{W}, {T}: Proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

When Bjarndyr Mender enters, other creatures you control get +1/+1 and gain indestructible until end of turn.

Indestructible (Damage and effects that say “destroy” don't destroy this creature.)
Whenever Declare, the Mother Bear deals combat damage to a player, put a +1/+1 counter on it.

Augmented — At the beginning of each end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Defected Explorer.

Unveil {3}{G}{W} ({3}{G}{W}: Transform this. Unveil only as a sorcery.)

Whenever Gallant Chevalier attacks or blocks, put a +1/+1 counter on it and each other creature you control with a +1/+1 counter on it.

You may exert Heavenly Bull as it attacks. When you do, it gains indestructible until end of turn. (An exerted creature won't untap during your next untap step.)
{3}{G}{W}: Destroy all nonland permanents with mana value 3 or less. Activate only if Heavenly Bull is attacking and only once.

Other untapped creatures you control have indestructible.
{2}{G}{W}: Target creature gains vigilance until end of turn.