msem-instigator

Sacrifice a creature: Put a +1/+1 counter on Bloodlash Caravan. Then if it's the only creature you control, it gains indestructible until end of turn.

Target creature gets +3/+2 and gains trample until end of turn.

Blooming Vista enters tapped.
{T}: Add {R} or {G}.
{1}, {T}: Add one mana of any color.

Whenever a creature dies, put a +1/+1 counter on Bog Apex.

Enchant creature
When Bogfume Pact enters, each opponent sacrifices a creature.
When enchanted creature dies, return it to its owner's hand.

Haste
Augmented — Whenever you cast a spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Bolstered Guardian. It loses this ability and gains “Whenever this attacks, it deals 2 damage to each of up to two targets.”

Deathtouch

Other Hounds you control get +1/+1.

Whenever Bourasan Street Watch attacks, you may pay {W}. If you do, Bourasan Street Watch gains indestructible until end of turn.

Target opponent discards two cards. (Cast a copy of this spell once while this creature is on the battlefield.)

Gain control of target permanent. (Cast a copy of this spell once while this creature is on the battlefield.)

Create two 1/1 green Insect creature tokens. (Cast a copy of this spell once while this creature is on the battlefield.)

Brushfire deals 3 damage to target creature. If that creature would die this turn, exile it instead.

Flash
Enchant creature
Enchanted creature gets +1/+1 and has hexproof.

Converge — Destroy up to X target artifacts or enchantments, where X is the number of colors of mana spent to cast Bury the Past.

Butcher deals 3 damage to target player. (Cast a copy of this spell once while this creature is on the battlefield.)

Deathtouch
Once each turn, you may cast a creature spell from your graveyard by paying life equal to its mana value rather than paying its mana cost.

Bwema, the Ruthless enters with your choice of two different counters on it from among menace, first strike, vigilance, and lifelink.

I — Exile the top card of your library face down.
II — Exile any number of cards from your hand face down.
III — Calamity of Yore deals damage to target creature or planeswalker equal to the number of cards you own in exile. Return all cards exiled with Calamity of Yore to their owners' hands.

Call of the Abyss deals 3 damage to any target and you gain 3 life.

Canid Simulacrum enters with each counter on it from among +1/+1, flying, first strike, deathtouch, lifelink, menace, reach, shield, trample, and vigilance. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
Whenever a creature you control enters, move two random counters from Canid Simulacrum onto that creature.

You may cast this spell with no targets for {2}{R}. If you do, as it resolves, create a 1/1 red Hound creature token, then attach Canine Acumen to that token.
Enchant creature
Enchanted creature gets +2/+0 and has first strike.

Other nonland permanents enter tapped.
Your opponents can't activate abilities of tapped permanents.

When Cave Eel enters, look at the top three cards of your library. Put one on top and the rest on the bottom in any order.

Double strike
Motley — As long as there are five or more names among nonland permanents you control, Champion of Blades has vigilance, trample, and haste.