msem-instigator

Captain Fina Redtail can't be blocked as long as you control another attacking Pirate.
Whenever Captain Fina Redtail deals combat damage to a player, you may pay {2}. If you do, create a 2/1 black and red Cat Pirate creature token with menace.

Whenever Battle-Scarred Combatant attacks or blocks, put a -1/-1 counter on it.

When Reverence Seeker dies, you may return another target Knight card from your graveyard to your hand.

Tap up to two target creatures.
Coalesce {5}{W}{W} (You may cast this from your graveyard for {5}{W}{W}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Heavens Claim Their Due enters tapped.

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Up to one target attacking creature gets +3/+3 and gains trample until end of turn.
Harmonize. (Trigger up to one harmony of a permanent you control.)

Lifelink
Revelation spells you cast cost {1} less to cast.

When Cave Eel enters, look at the top three cards of your library. Put one on top and the rest on the bottom in any order.

Enchant player
At the beginning of enchanted player's upkeep, that player creates a 1/1 white Soldier creature token.

Instant and sorcery spells you cast cost {1} less to cast.

When Ol' Sycamore enters, choose up to two —
• Ol' Sycamore fights another target legendary creature.
• Destroy target noncreature storied permanent. (Enchantments and legendary permanents are storied.)

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.

Whenever another creature named Ainok Pack you control enters, you gain 2 life.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
{T}: Add {G}{G}.

Lionize {1}{U} ({1}{U}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Sacrifice this creature: Counter target instant or sorcery spell unless its controller pays {X}, where X is this creature's power.

Flying
Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
Whenever a cursed opponent draws a card, you may draw two cards.

Equipped creature gets +2/+1 and has trample.
Whenever equipped creature attacks, other Citizens and Peasants you control get +2/+1 and gain trample until end of turn.
Equip {3}

Whenever attackers are declared, defending player may pay 2 life for each creature you control attacking them. Then target creature gets -X/-X until end of turn, where X is the number of times that player didn't pay life this way.

Defender
{T}: Smoldering Djinni deals 1 damage to each opponent.
Whenever you cast a red spell, untap Smoldering Djinni.

Whenever you cast a white spell, target player loses 2 life and you gain 2 life.
Whenever you cast a green spell, put a +1/+1 counter on Corrupted Warlord.

This spell can't be countered.
Draw a card.
Reprise {2}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

As long as it's your turn, Ahl the Omenwing is a 2/1 Bird Wizard creature with flying and indestructible. (He doesn't lose loyalty while he's not a planeswalker.)
[+1]: Surveil X, where X is the number of creatures that attacked this turn.
[–2]: Return target nonland permanent to its owner's hand. Draw a card.

Rhapsody {4}{U}{U} (Pay {4}{U}{U} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
When Unstable Prophet enters, surveil X, where X is its power. (Look at the top X cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Flash
Enchant permanent
Whenever enchanted permanent deals damage to an opponent, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

When Journey to the Otherworlds enters, draw a card, then choose a creature card name.
Whenever a creature you control with the chosen name attacks, you may aetherize it. (To aetherize, create a token that's a copy of it, then exile that token.)