msem-instigator

Flying, menace
Whenever another creature you control deals combat damage to a player, sacrifice it.
If you would draw a card, you may instead return a creature card from your graveyard to your hand.

When Threshing Sundew enters, merge up to one target creature card in your graveyard under it. Threshing Sundew has that card's abilities.
When Threshing Sundew dies, return all other cards merged with it to their owner's hand.

Flying, first strike, vigilance, trample, lifelink
{4}: Put a +1/+1 counter on Alin and Meva, Warqueens.

Whenever Beragnian Brawlmaster or another Warrior you control enters, that Warrior fights target creature an opponent controls.
{R}{W}: Target Warrior creature gets +1/+1 until end of turn.

When Callous Renegade enters, you may return target Rebel creature card with mana value 4 or less from your graveyard to the battlefield. It gains haste until end of turn.

Battalion — Whenever Callous Trainer and at least two other creatures attack, create a 1/1 white Warrior creature token that's tapped and attacking.

Once each turn, when a creature you control attacks alone, you may untap target attacking creature. After this combat, there's an additional combat step.

Flying
When Cyrukan's Messenger enters, you may search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
Whenever Cyrukan's Messenger attacks, you may put an Equipment card from your hand onto the battlefield attached to Cyrukan's Messenger.

Haste
Battalion — Whenever Fellor Tactician and at least two other creatures attack, creatures you control get +1/+1 until end of turn.

Flying, first strike, haste
Whenever you gain life, you may have Gisela, Blade of Morning deal that much damage to any target. Do this only once each turn.

Rhapsody {5}{R}{W} (Pay {5}{R}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Whenever a creature you control with power 4 or greater attacks, look at the top four cards of your library. You may cast a nonland card with mana value 3 or less from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

Livia's name is Senaturian Legion in addition to its other names as long as it's on the battlefield.
At the beginning of your upkeep, conjure a card named Senaturian Legion into your hand, then discard a card. (It's a 1/1 Human Soldier for {W}{W} that gets +1/+1 for each other creature on the battlefield named Senaturian Legion.)
Other Soldiers you control have haste.

When Qulai enters, look at the top six cards of your library. You may reveal a Fox card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
Sacrifice Qulai: Foxes you control gain hexproof and indestructible until end of turn.

Indestructible
Battalion — Whenever Rallios, Heir to the Evil One and at least two other creatures attack, creatures you control get +1/+0 and gain double strike until end of turn.

Whenever you cast an instant or sorcery spell, create a 1/1 red and white Sand enchantment creature token with lifelink and haste.

Whenever Shina Taiyohata or another creature you control enters, you may have that creature gain haste. If you do, return that creature from the battlefield to its owner's hand at the beginning of the next end step.

First strike, haste
Whenever Soulflare Nymph deals damage to a creature, exile that creature.

Trample
When Ainok Scout enters, nourish 2, then return a creature you control to its owner's hand. (To nourish 2, either put two +1/+1 counters on this creature or create two 1/1 white Citizen creature tokens.)

Flying
At the beginning of your upkeep, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Flash
Players can't discard cards.
Whenever Gim-Chimya, the Invisible attacks, it can't be blocked this turn unless defending player pays {1} for each card in your hand.

Creature spells you cast cost {1} less to cast for each of their creature types that no creature you control has.
Whenever you cast a creature spell, if it has a creature type no creature you control has, draw a card.

First mate—Each nonland card in your starting deck has the same name as exactly one other card in your starting deck. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Vigilance
Whenever you cast a spell with the same name as a card in your graveyard, draw a card.

Hollow Queen can't be blocked by tokens.
Whenever Hollow Queen deals combat damage to a player or planeswalker, you may remove a counter from a permanent you control. If you do, put a +1/+1 counter on target creature you control.

When Hooded Inquirers enters, draw two cards.

Whenever Instability Elemental enters or you draw a card except during your draw step, target creature gets +1/+1 until end of turn.