msem-instigator

Flying
Whenever Frenzied Sylph attacks or blocks, you may pay {R}. If you do, it gets +3/+0 until end of turn. Exile it at the beginning of the next end step.

Flash
Flying
When Gale Conjurant enters, return target spell to its owner's hand if its mana value is less than or equal to the number of creatures in Gale Conjurant's pack. (Two or more creatures you control with equal power are in a pack.)

When Gusma's Artisan enters, search your library for a card, then shuffle and put that card on the bottom of it.
{2}{U}, Sacrifice Gusma's Artisan: Manifest the bottom card of your library. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Prowess
Gusma's Emissary gets +1/+1 as long as you control a black or green permanent.

When Hardlight Visionary enters, create a Function token with “Until end of turn, target creature becomes a 5/5 Dragon and gains flying.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Flying
{T}, Tap another untapped creature in Heaven's Gale Harrier's pack: Tap target creature. (Two or more creatures you control with equal power are in a pack.)

When Hermetic Fisher dies, you may return target creature to its owner's hand.

Flying
When Highspire Informant enters, scry 1.

Flying
Whenever Hoff's Scout deals combat damage to a player, you may scry 1.

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.)
Hopeless Wanderer can't be blocked.

You have no maximum hand size.
Whenever a player casts a spell, put a +1/+1 counter on Humar.
At the beginning of your upkeep, target player draws cards equal to Humar's power.

Imitator of Drakes has flying as long as it has a +1/+1 counter on it.
{2}{U}: Put a +1/+1 counter on Imitator of Drakes.

When Imperial Diplomats enters, if it's not a token, create a token that's a copy of it, except it has no mana cost.
{T}, Tap an untapped creature you control: Draw a card, then discard a card.

Sleight (You may cast this spell as though it had flash if you pay {1} more to cast it.)
Enchant creature you don't control
Embody (Enchanted creature is a copy of this card except for its types.)

Whenever Inquisitive Guardian deals combat damage to an opponent, you may exile a nonland card from your graveyard. If you do, draw a card.
{U}: Inquisitive Guardian gains flying until end of turn.

Hexproof
Invisible Stalker can't be blocked.

When Jidai Clairvoyant enters, create a 2/2 colorless Spirit creature token.
Whenever a colorless creature you control enters, you may draw a card.

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.”

Lionize {2}{U} ({2}{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.)
Whenever this creature deals combat damage to a player, draw that many cards.

Masked Impersonator can't be blocked.
Art of war — At the beginning of your end step, if Masked Impersonator dealt damage to an opponent this turn, you may have it become a copy of target creature you control except it has this ability.

Flying
When Mei's Understudy enters, if you control another Actor, draw a card.

Flash
Flying
When Meletis Stratomancer enters, target creature an opponent controls gets -2/-0 until end of turn.

{T}: Draw a card, then discard a card.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
You may cast the first spell that's an enchantment, instant, or sorcery with mana value 1 you cast each turn without paying its mana cost.