msem-instigator

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever Manipulator of Waves attacks, mill three cards. Then create a 0/0 blue Elemental Serpent creature token with “This creature gets +1/+1 for each five cards in your graveyard.”

When Impatient Busker enters, you may put a lore counter on target Saga.

Flying
Spirited (When this creature enters, you may activate one of its activated abilities without paying its costs.)
Harmony — Draw three cards.
{2}{G}{G}: Harmonize. (Trigger up to one harmony of a permanent you control.)

Spells cost {1} more to cast for each colored mana symbol in their mana cost beyond the first. (For example, a spell with mana cost {W}{W} would cost {1}{W}{W} to cast.)

Flying, trample
Whenever Bretala of Redsky attacks, it gains double strike until end of turn unless defending player sacrifices a creature.

Art of war — At the beginning of your end step, if Masamori Ranger dealt damage to an opponent this turn, search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Vigilance
Resolute — Whenever East Ward Champion attacks, attacking creatures you control gain indestructible until end of turn if East Ward Champion's power is greater than its base power.

Whenever another creature with power 4 or greater you control attacks, Ruthless Brawler deals 1 damage to defending player.

Whenever a nontoken creature you control dies, create a 1/1 black Skeleton creature token.

This spell costs {1} less to cast for each Desert you control.
When Crested Crustacean enters, return target permanent to its owner's hand.

When Skhorvall Raider enters, if you control an embattled creature, Skhorvall Raider deals 2 damage to any target. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Prowess
{T}: Catalyze, then catalyze again. Activate only if Sigil Slinger's power is 5 or greater. (The next spell you cast this turn costs {2} less to cast.)

Search your library for a creature or sorcery card, put it into your graveyard, then shuffle.
Reconstruct {2}{B} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

Trample
Chained Ravager can't attack or block unless a player has lost life this turn.

Equipped creature gets +1/+0 and has poisonous 1. (Whenever it deals combat damage to a player, that player gets a poison counter.)
Equip {1}

Scry 5.

Vigilance
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Whenever Silvercrest Sentry attacks, untap up to one target legendary creature you control.

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.

Target creature gains hexproof until end of turn.
Monument {2}{U} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

{2}, {T}: Tap target creature.

Defender
As long as you control an enchantment, Rooted Cavalier has vigilance and can attack as though it didn't have defender.

(Activate each ability only once as a sorcery. You gain the realm's favor after activating them all.)
{W}: Put a first strike counter on target creature.
{1}{W}: Invigorate 2. (Choose a creature with the least power among creatures you control and put two +1/+1 counters on it.)
{2}{W}: Create two 1/1 white Soldier creature tokens.
Creatures you control with counters on them have flying and lifelink.

Mill a card. Target creature gets -X/-X until end of turn, where X is the number of cards put into your graveyard from anywhere this turn.

Trample
Rift Prowler enters with X +1/+1 counters on it, where X is your fealty to Forests. (Each Forest you control counts towards your fealty to Forests.)

Flash
When Nurse Trainee enters, you may prevent the next 2 damage that would be dealt to another target creature this turn.