msem-instigator

Enchant creature
Enchanted creature gets +1/+1.
When enchanted creature dies, return another target creature card from your graveyard to your hand.

When Ghoulsaber enters, create a 1/1 white Spirit creature token with flying, then attach Ghoulsaber to it.
Equipped creature gets +2/+2.
Equip {2}

{T}: Add {C}.
{3}{U}: Until end of turn, I's Observatory becomes a 1/4 creature. It's still a land. It has menace if {B} was spent to activate this ability, has first strike if {R} was spent, and assigns combat damage equal to its toughness rather than its power if {G} was spent.

Flash
Haste
{3}, {T}: Exchange control of two target noncreature spells. Their controllers may choose new targets for the spells.

Look at the top three cards of your library. Put one of them into your hand. Put Lost in Deep Storage and the rest on the bottom of your library in any order.

Flying
Other creatures get -1/-1.
Whenever Pan Long enters or deals combat damage to a player, return to the battlefield under your control target creature card from a graveyard that was put there from the battlefield this turn.

Flying
Concord — When Judicious Djinni enters, if there are four or more card types among permanents you control, return target instant or sorcery card from your graveyard to your hand.

Desert Storm deals 6 damage to target creature.

Prowess
{U}: Sage of the Aurora gains flying until end of turn.

Oldgrove Nurturer enters with a +1/+1 counter on it.
{G}, Remove a +1/+1 counter from a creature you control: Create a 1/1 colorless Construct artifact creature token.

{T}, Sacrifice Fortune Charm: Look at the top two cards of your library, then put them back in any order. Draw a card.

Whenever you cast a noncreature spell, Novice Pyromancer deals 1 damage to target player or planeswalker.

When Folded Fan Recruit enters, invigorate 1. (Choose a creature with the least power among creatures you control and put a +1/+1 counter on it.)

Flying
When Courier Eagle enters, target creature gets +2/+1 until end of turn.

Null Bit deals 3 damage to any target.
You may discard a card. If you do, draw a card.

Codex — Hannah, Aethertechnician; Flynn Skara; Pidge, Tinkering Courier; Reyhsia, Truth Chaser. (As this enters, conjure its contents into a shuffled face-up additional library.)
You may spend mana as thought it were mana of any color to cast this codex's contents.
Sacrifice Karina's Connections: Copy target activated ability of one of its contents. You may choose new targets for the copy.

Thunderous Applause deals damage to any target equal to the number of tapped creatures you control.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a nontoken creature you control enters, you may pay {1}{W}. If you do, create a 1/1 white Bird creature token with flying.

Flying
When Cormoran, Raven Monarch enters, you may put target creature card with mana value 3 or less from a graveyard onto the battlefield under your control.

Discard two cards, then draw a card for each card discarded this way. Night of Falling Stars deals damage equal to the total mana value of the discarded cards to each creature.

Counter target spell.
Create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Changeling (This card is every creature type.)
Watcher of the Polyps has all names of creature cards in addition to its name as long as it's on the battlefield.
Watcher of the Polyps gets +X/+X, where X is the greatest number of creatures you control with the same name.

Menace
Deploy 4 (As this enters, you may tap any number of other creatures you control with total power 4 or more.)
When Street Raider enters deployed, discard your hand, then draw three cards.

Colossal 4—{5}{U}{U}{U} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {5}{U}{U}{U} as a sorcery: Put four +1/+1 counters on it if it has none.)
Whenever Megalokraken enters or attacks, reveal the top X cards of your library, where X is Megalokraken's power. You may cast a noncreature spell with mana value X or less from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

{X}, {T}: Search your library for a creature card with mana value X or less and no creature types noted by Memorial to Sir Jasper, put it onto the battlefield, then shuffle. Note that creature's creature types. Activate only as a sorcery.