msem-instigator

{1}{U}, {T}: Reveal the top card of your library. If it doesn't share a color with Heretical Seer, put it into your hand.

Spirited (When this enters, you may activate one of its activated abilities without paying its cost.)
{1}, {T}, Discard a card: You gain 4 life.
{2}, {T}, Pay 2 life: Create a 1/1 colorless Construct artifact creature token. It can't block this turn.
{3}, {T}, Sacrifice a permanent: Draw a card.

Flying
When Sunchaser Mantas enters, choose a color. Look at the top four cards of your library. You may reveal a card of the chosen color from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Motley — This spell costs {3} less to cast as long as there are five or more names among nonland permanents you control.
Destroy all creatures.

Flying
{1}, Sacrifice a creature: Put a +1/+1 counter on Bloodthirsty Manticore. It gains indestructible until end of turn. Tap it.
Surpass {4}{B}{R} ({4}{B}{R}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Tap up to two target creatures an opponent controls. Those creatures don't untap during their controller's next untap step.
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.”)

Glorious end — When Warband Commander dies, if it was tapped, put a +1/+1 counter on each creature you control that attacked this turn.

Flash
Flying
When Mellan enters, exile up to one other target nonland permanent with mana value equal to or less than the number of creatures you control with flying until Mellan leaves the battlefield.

Flash
Enchant creature
When Moved by Instinct enters, put a +1/+1 counter on enchanted creature.
Enchanted creature has haste and trample.

Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Fogborn Mauler enters or leaves the battlefield, you gain 2 life.

Return up to three target land cards from your graveyard to your hand.
Coalesce {6}{G} (You may cast this from your graveyard for {6}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Enchant creature
When Make Way enters, draw a card.
Enchanted creature can't block.

As long as Inconspicuous Platypus is enchanted or equipped, he's a 3/3 legendary Platypus Rogue named Agent P and can't be blocked.

You may play an additional land this turn.
Draw a card.

Whenever equipped creature deals combat damage to a player, return to your hand all cards from your graveyard that were put there this turn.
Equip {3}

Lifelink

Deathtouch
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Kicker {2}{R} (You may pay an additional {2}{R} as you cast this spell.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
If Mountain Victor was kicked, it enters with two +1/+1 counters on it.

Equipped creature gets +2/+1.
Equipped creature has first strike as long as it's attacking.
Whenever a Knight or Soldier you control attacks, you may attach Chevalier's Lance to it.
Equip {3}

First strike, hexproof

Flying, lifelink
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Recreator of Myths attacks, you may cast target instant or sorcery spell from your graveyard. If you do, exile that card instead of putting it into your graveyard as it resolves.

Target creature can't block this turn.
Inscribe {1}{R} ({1}{R}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

When Datalith enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)
{T}: Add one mana of any color.

Other Angels and Nephilim you control get +1/+0.
{3}{W}: Until end of turn, Hooded Mystic becomes an Angel, gets +3/+3 and gains flying.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Whenever Aleud Pathfinder becomes blocked, untap up to two lands you control.