msem-instigator

Harmony — Target creature gains haste until end of turn.
When Streetside Entertainer enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Sunset Cliffs Hunter gets +1/+0 and has first strike as long as a player controls a permanent with a bounty counter on it.

Sycophantic Aristocrat gets +2/+1 as long as you control another Noble.

Haste
Art of war — At the beginning of your end step, if Teikoku Skirmisher dealt damage to an opponent this turn, put a +1/+1 counter on it.

Prowess
Whenever you cast an instant or sorcery spell, Tirenan Pyromancer deals 1 damage to each opponent.

{2}{B}: Return Torchlight Tormentor from your graveyard to your hand. If you do, each opponent loses 1 life.

Haste
Sacrifice a land: Trail Blazer explores. You may put a basic land card from your hand onto the battlefield tapped. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then you may put that card in your graveyard.)

Rhapsody {4}{R}{R} (Pay {4}{R}{R} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Double strike

Whenever V-4 Fixit or another artifact you control enters, target creature you control gets +1/+1 until end of turn.

At the beginning of each end step, if you've cast a noncreature spell this turn, Void Sculptor deals 1 damage to each opponent.

Haste
Glorious end — When Warband Lieutenant dies, if it was tapped, put a +1/+1 counter on another target creature you control.

Whenever you cast a noncreature spell, Wild Pyromancer gets +1/+1 until end of turn.
Whenever Wild Pyromancer attacks, you may pay {2}{R}. If you do, transform Wild Pyromancer.

Haste
Ride {R} ({R}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Ferocious — At the beginning of each combat, if you control a creature with power 4 or greater, Worshipper Whelp gets +2/+0 until end of turn.

Trample
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Haste
When Zipping Zapper enters, target creature gains haste and first strike until end of turn.

When AOSE Extractor enters, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

{T}: Add one mana of any type that a land an opponent controls could produce.

Aleud Beastmaster has frenzy X, where X is the number of unblocked attacking creatures you control. (Whenever it attacks and isn't blocked, it gets +X/+0 until end of turn.)

Trample
Arpechian Champion can only attack or block alone.
Whenever a land you control enters, put a +1/+1 counter on Arpechian Champion.

When Artian, Phyrexian Architect enters, search your library for a land card, put it onto the battlefield, then shuffle.
At the beginning of your upkeep, put a corruption counter on a land you control. Then create a 1/1 colorless Phyrexian artifact creature token for each land you control with a corruption counter on it.

When Backwoods Cultivator enters, put a +1/+1 counter on target creature you control.
When Backwoods Cultivator dies, proliferate. (You choose any number of permanents and/or players with counters on them, then give each another kind of a counter already there.)

Deathtouch
Bahet's Emissary gets +1/+1 as long as you control a white or black permanent.

Trample
When Bank Skimmer enters, create a green Aura enchantment token named Turtle's Valor attached to target creature. The token has enchant creature and “Enchanted creature gets +X/+X, where X is its mana value.”