msem-instigator

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.

{2}{R}: Creatures you control get +1/+0 until end of turn.
{1}{G}: Creatures you control gain trample until end of turn.

Flash
When Ambush Gharial enters, it fights up to one target creature. If that creature would die this turn, exile it instead.

Whenever a source you control deals damage to a creature or planeswalker an opponent controls, exile that creature or planeswalker.

When Endmire Scourer dies, search your library for a card with mana value 4 or less, reveal it, put it into your hand, then shuffle.

Advance {1}{R} (Cast this for {1}{R} to advance it as it enters. {1}{R}: Advance this as a sorcery.)
Whenever Blitz Breaker advances, its power becomes equal to the amount of noncombat damage that's been dealt to your opponents this turn. (This effect lasts indefinitely.)

Enchant creature
As Legacy of Frondpond enters, choose a creature type.
Enchanted creature gets +2/+1, has deathtouch, and is the chosen type in addition to its other types.

[0]: Sacrifice a creature. When you do, Xiong Mao, Survivalist deals damage to any target equal to that creature's power, then put a number of loyalty counters on Xiong Mao equal to that creature's toughness.
[–2]: Return up to two target creature cards from your graveyard to your hand.
[–6]: You get an emblem with “Whenever a creature you control dies, you may draw cards equal to its power, then you may gain life equal to its toughness.”

[+1]: Until end of turn, up to one target creature gets +1/+0 and can't be blocked.
[–2]: Exile target artifact or enchantment.
[–5]: You get an emblem with “Untap all permanents you control during each other players untap step” and “Draw a card during each other player's draw step.”

Each other Rogue creature you control enters with an additional +1/+1 counter on it.
Remove a +1/+1 counter from a creature you control: That creature can't be blocked this turn.

When Allagras' Vanguard enters, create two 1/1 blue Merfolk creature tokens with “When this creature dies, draw a card, then discard a card”.

Vigilance (Attacking doesn't cause this creature to tap.)

Counter target spell. If you are glorious, draw a card. (You are glorious as long as you have a glory counter.)

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{4}{G}: Target creature gets +2/+2 until end of turn.

Choose one —
• Target creature gets +0/+3 until end of turn.
• Target creature gains flying and lifelink until end of turn.

Whenever Boghex Witch deals combat damage to a cursed player, that player loses the game.
{2}{B}: Look at the top five cards of your library. You may reveal a Curse card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

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.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Sword Dance deals 3 damage to target attacking or blocking creature. If you're in a renaissance, Sword Dance deals 5 damage to that creature instead.

Flying, haste
Ward—Pay 3 life.
The first Dragon spell you cast each turn costs {R}{R} less to cast. (This can reduce the amount of generic mana you pay.)

Target permanent you control gains protection from your opponents until end of turn.
Draw a card.

Menace
Whenever CySec Blacksuit deals combat damage to a player or planeswalker, create a Function token with “Choose a nonland card exiled by this spell. For as long as that card is exiled, you may cast it and you mana of any type can be spent to cast that spell.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

When Broadside Raider enters, create a 1/1 blue and red Pirate creature token with haste.

Return all creature and planeswalker cards from your graveyard to the battlefield.

First strike
{1}{R}: Transform Embercut Duelist. Activate only if it's attacking.