msem-instigator

Whenever Bold Vanquisher attacks, upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Trample

Target creature and all other creatures with the same name as that creature get +2/+0 until end of turn.

Target creature gains indestructible until end of turn.

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature doesn't untap during its controller's untap step.

Assault {1}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Bone Mesa Marauder assaults, it gains flying until end of turn.

Equipped creature gets +1/+0.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Whenever another creature you control dies, you may pay {1}. If you do, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

When Boneweary Warrior dies, you may put a -1/-1 counter on target creature.

Deathtouch

Return target nonland permanent you control and target nonland permanent you don't control to their owners' hands.

When Borderland Garrison enters, it deals 1 damage to up to one target creature and 1 damage to you.

Assault {R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Borsuppa Outrider assaults, it deals 2 damage to each opponent.

Whenever Borsuppa Roughrider attacks, create a colorless Desert land token named Scoured Path with “{T}: Add {R}.” Sacrifice that token at the beginning of the next end step.

Menace (This creature can't be blocked except by two or more creatures.)
Assault {R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)

{2}, Sacrifice Bottled Fate: Put the top card and bottom card of your library into your hand.

Whenever Bound Apparition becomes the target of a spell or ability, put a -1/-1 counter on it.

Flying, prowess
When Bound Watcher enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

When Boundary Hallowblade enters, create a white Aura enchantment token named Consecration Blessing attached to target land. The token has enchant land and “Enchanted land is named Hallowed Ground and has indestructible.”

Flying
Whenever you attack, another target creature you control gains flying until end of turn.
Fleeting {U} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Bounty Crusher has trample as long as it's being blocked by a marked creature.

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.

Untap target creature you control. It gets +4/+4 and gains reach until end of turn.

Trample
{1}{G}: Brackish Kelpie gets +2/+2 until end of turn. Activate only once each turn.

{1}, Sacrifice Brackwater Scuttler: Draw a card.