msem-instigator

Put a +1/+1 counter on target creature. It gains hexproof until end of turn.

When Skittering Atrocity enters, up to one target creature gets -X/-X until end of turn, where X is the number of Horrors you control.

When Slyten Analyst enters, you may search your library for a card, then shuffle and put that card on top. If you do, you lose 2 life.

Whenever Slyten Connoisseur attacks, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)
Once each turn, when an artifact you control dies, you may pay 1 life. If you do, draw a card.

Whenever Slyten Jewel Runner attacks, target creature can't block until end of turn.
Augmented — At the beginning of your end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Slyten Jewel Runner.

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
Augmented — If you've spent {W}{U}{B}{R}{G} to cast spells this turn, put two of those cards into your hand instead.

As an additional cost to cast this spell, discard a card.
Draw two cards and crystallize twice. (Put a +1/+1 counter on a creature you control or create a Treasure. Then do it again.)

Reveal the top five cards of your library. You may put a permanent card revealed this way into your hand and the rest into your graveyard.

Solar Pulse deals 3 damage to target attacking or blocking creature.

Enchant permanent
Enchanted permanent is a land with “{T}: Add {G}{W}{U}” and loses all other card types and abilities.
{1}, Discard Song of Shoals: Add one mana of any color. Scry 1.

Spend only black mana on X.
Any number of target players each draw X cards and lose X life.

Flying
When Spawn of Keranos enters, you may draw a card. If you do, discard a card unless you control another creature with flying.

Whenever you cast a noncreature spell, create a 1/1 colorless Servo artifact creature token.
{1}{U}, {T}, Exile three noncreature cards from your graveyard: Draw a card.

Haste
Ward—Sacrifice a creature.
Spinning Gears Abomination enters with X +1/+1 counters on it.
Spinning Gears Abomination can't attack alone.

For each creature you control, put a +1/+1 counter on it or create a Treasure token.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Another target creature you control gets +1/+1 until end of turn.
[Lore III] Search your library for a basic land card, put it onto the battlefield, then shuffle.

Menace
Stalker of Myth gets +1/+0 for each creature you control with chronicle.
{2}, Remove a counter from a permanent you control: Draw a card, then discard a card.

Flying
Starbane Elemental's power and toughness are each equal to the number of creatures with flying you control.
When Starbane Elemental enters, destroy all creatures without flying.

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand. You may cast a nonland card with mana value 3 or less from the other pile without paying its mana cost, then put that pile into your graveyard.

Flash
Enchant creature
Enchanted creature gets +1/+1 for each enchantment you control.

At the beginning of your end step, you may sacrifice a permanent. When you do, return target creature card from your graveyard to your hand.

Augmented — If you've spent {W}{U}{B}{R}{G} to cast spells this turn, you may play Start Over without paying its mana cost.
Put target creature or planeswalker on the bottom of its owner's library.

Colossal 3—{4}{R} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {4}{R} as a sorcery: Put three +1/+1 counters on it if it has none.)
When Storm-Eye Salamander's colossal ability puts one or more counters on it, exile the top three cards of your library. Until the end of your next turn, you may play one of those cards.

Vigilance
{4}{U}: Draw a card.

Flash
Enchant creature
Enchanted creature gets +1/+1 and has “Whenever this creature deals combat damage to an opponent, draw a card.”