msem-instigator

Whenever one or more creatures you control deal combat damage to a player, you may destroy target artifact or enchantment that player controls.
Whenever you cast a green creature spell, create a 3/3 green Wurm creature token with trample.

Each player may search their library for a creature card, reveal it, and put it into their hand. Then each player who searched their library this way shuffles it.

({T}: Add {U} or {R}.)
Steamlit Peaks enters tapped.
{1}, {T}: Add {U}{U} or {R}{R}.

Cannonblast deals 5 damage to target creature. If you control a Pirate, Cannonblast deals 3 damage to that creature's controller.

Whenever a land you control enters, upgrade target creature. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Vigilance
• Trample

{T}: Add {C}.
{T}: Add {B}, {G}, or {U}. You can't spend this mana to cast a monocolored spell.

When Precursor Custodians enters, exile up to one target creature. As long as that card remains exiled, its owner may cast it. A spell cast this way costs {2} more to cast.

As an additional cost to cast this spell, exile a red card from your hand.
Destroy target artifact. Awaken to the Skies deals damage to that artifact's controller equal to its mana value.

[+1]: Until end of turn, Winmeari, Glorian Defector becomes a 4/4 Angel creature with flying and lifelink that's still a planeswalker. Prevent all damage that would be dealt to her this turn.
[0]: Create a 2/2 black Zombie creature token.
[–1]: You get an emblem with “Attacking creatures your opponents control must attack a Winmeari planeswalker if able.”

Target creature gets +4/+3 until end of turn. Put a trample counter on it.

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{1}{R}{G}: Warriors you control get +1/+0 and gain trample until end of turn.

Motivate 1 (When this creature enters, you may motivate target creature with less power than this by putting a +1/+1 counter on it.)
{2}{W}{W}: Exile Valtrian Cavalier, then return it to the battlefield under your control.

Fox of the Fallen Forest gets +4/+0 as long as you control a legendary creature.

This spell can't be countered.
Coppergild Mercenary has hexproof as long as it has one or more counters on it.
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.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever Happy Manta deals combat damage to a player, draw a card for each card type among spells you've cast this turn.

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

Whenever an enchantment you control enters, draw a card.

When Abberant Frostbringer enters, tap up to one target creature. If you do, put two stun counters on that creature. (If a permanent with a stun counter would become untapped, remove one from it instead.)

[+1]: Untap up to one target creature.
[0]: Edith Waunt becomes a legendary green Human creature with “This creature's power and toughness are each equal to the number of loyalty counters on it” and “Whenever this creature deals damage, put a loyalty counter on it” until your next turn.

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Masked Lancer has first strike as long as it's attacking.
Whenever Masked Lancer mentors a creature, that creature gains first strike until end of turn.

Meandering Path enters tapped unless you control one or fewer other lands.
{T}: Add {R} or {G}.
Cycling {2} ({2}, Discard this card: Draw a card.)

When Bearer of Old Growth enters, choose one —
• Untap up to two target artifacts.
• Draw a card.

Whenever Portal Inhibitor attacks, exile target nonland card from defending player's graveyard. Copy it. You may cast the copy. (You still pay its costs, including color. Copies of permanents enter as tokens.)

Indestructible
Legendary permanents you control have indestructible.