msem-instigator

Untap target creature. It gets +2/+2 and gains hexproof until end of turn.

Up to two target creatures can't block this turn.

Whenever Twilight Walker perseveres, target creature doesn't untap during its controller's next untap step. (A creature perseveres when it survives damage.)

Unassuming Waif can't be blocked.
Unassuming Waif gets +1/+0 for each other Warrior you control.

Enchant creature
Enchanted creature can't be blocked.
{1}{G}: Enchanted creature gets +1/+1 and gains hexproof until end of turn.

Undine Coven gets +1/+1 for each other Merfolk you control.
Whenever you cast a noncreature spell, Undine Coven deals 1 damage to target player or planeswalker.

Starting with you, each player may sacrifice a creature. Each player that doesn't loses life equal to the total power of creatures sacrificed this way.

Exile the top five cards of your library. Until end of turn, you may play any number of cards exiled this way with mana value less than or equal to the number of colors among permanents you controlled as you cast United Fervor.

Create X 1/1 white Nymph creature tokens. Until end of turn, creatures you control gain protection from each color among permanents you controlled as you cast United Force.

Draw two cards, then discard two cards.

Flash
Deathtouch

{T}: Target attacking or blocking creature gets +1/+1 until end of turn.

Menace (This creature can't be blocked except by two or more creatures.)
Engage (This creature must be blocked each combat if able.)

Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Vigilance
Engage (This creature must be blocked each combat if able.)
Other Soldiers you control get +1/+1 and have first strike.

Target creature gains indestructible until end of turn.
Draw a card.

Counter target creature or planeswalker spell.

Whenever one or more creatures attack you or a planeswalker you control, reveal the top card of your library, then put a -1/-1 counter on each attacking creature with the same mana value as the revealed card.

Whenever Veiled Charmer attacks, target creature blocks it this turn if able.

Primal {1}{B}{B} (During your turn, you may cast this spell for {1}{B}{B} instead of playing a land.)
Deathtouch
When Venomous Gorran enters, if you cast it for its primal cost, it fights target creature.

Reach
Whenever Venomtongue Archer deals damage to a creature, put that many -1/-1 counters on that creature.

{T}, Sacrifice Vibrant Rainforest: Search your library for a Mountain or Forest card and put it onto the battlefield tapped, then shuffle.

Equipped creature gets +1/+3.
Whenever another creature blocks or becomes blocked by equipped creature, that creature loses all abilities until end of turn.
Equip {3}

Sacrifice Voice of Ambition: Target creature gets +2/+1 until end of turn.

{T}, Discard two cards: Draw two cards, then Voice of Warryn deals 2 damage to each opponent.