msem-instigator

Rhapsody {4}{W}{W} (Pay {4}{W}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Triumvirate Strategist has first strike as long as it's attacking.

At the beginning of your upkeep, if you control a legendary creature, put a +1/+1 counter on Trossingen Warden.

Create two 1/1 white Soldier creature tokens with melee. (Whenever that creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)

Destroy target creature with power, toughness, or mana value 4 or greater.

(Transform this if it's not attached to a creature. Pay {2}{W} as a sorcery to unattach it.)
Enchant creature you control
Trusty Steed's rider gets +2/+2.

Flash
Flying
When Turela, Defiant Angel enters the battlefield, exile all other creatures you control. Return them to the battlefield under their owner's control at the beginning of the next end step.

When Twilight Vigil enters the battlefield, scry 2, then put a night counter on it.
Death knell — Put a night counter on Twilight Vigil. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)
Sacrifice Twilight Vigil: For each night counter on it, you gain 1 life and trigger up to one death knell of a permanent you control.

Whenever Twilight Walker perseveres, target creature doesn't untap during its controller's next untap step. (A creature perseveres when it survives damage.)

Each creature you control with a +1/+1 counter on it has double strike.
If one or more +1/+1 counters would be put on a creature you control, put that many plus one +1/+1 counters on that creature instead.

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.)
Lifelink

Double strike
Ride {2}{W} ({2}{W}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Enchant creature
When Twinklewings enters the battlefield, draw a card.
Enchanted creature has flying.

Creature tokens you control get +1/+1 and have distorted. (They can be blocked by tapped creatures but not untapped creatures.)

Double strike
Whenever an Equipment enters the battlefield under your control, create a 3/3 white Archon creature token with flying and attach that Equipment to that token.

Flying, vigilance
When Tyriel, Angelic Artisan enters the battlefield, you may search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
Whenever Tyriel attacks, you may put an Equipment card from your hand onto the battlefield, then attach it to Tyriel.

Archive 4 (As this enters the battlefield, shuffle the top four cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, destroy all nonland permanents you don't control with the same mana value as the drawn card.

You may pay {W} and tap an untapped Monk you control rather than pay this spell's mana cost.
The next 3 damage that would be dealt to you and/or permanents you control this turn is dealt to any target instead.

When Unbound Expanse enters the battlefield, if an opponent controls more lands than you, create a Plains token. (It's a basic land with “{T}: Add {W}.”)
{1}{W}, Sacrifice Unbound Expanse: Exile each nonland permanent you control, then return those cards to the battlefield under your control.

Destroy target artifact or enchantment. You gain life equal to its mana value.

When Unburdening Priest enters the battlefield, you may exile any number of creatures you control not named Unburdening Priest, then return those cards to the battlefield under your control.

Whenever a creature you control is dealt damage, put a +1/+1 counter on that creature.

When Uncovered Secrets enters the battlefield, search your library for an artifact card, reveal that card, then shuffle and put that card on top.
Concord — Creatures you control get +1/+1 as long as there are four or more card types among permanents you control.

Vigilance
Whenever Underpass Sentinel enters the battlefield or attacks, you may put a +1/+1 counter on another target creature you control without one.
Sacrifice Underpass Sentinel: Embattled creatures you control gain hexproof and indestructible until end of turn. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Return up to two target creature cards with total mana value 4 or less from your graveyard to the battlefield.