msem-instigator

Whenever a land you control enters, you may have target creature get +1/+0 and gain first strike until end of turn.

When Seven Deadly Sins has seven or more sin counters on it, sacrifice it.
{B}{B}, Put a sin counter on Seven Deadly Sins: Destroy target creature. This ability costs {1} more to activate for each sin counter on Seven Deadly Sins.

Coastal Metropolis enters tapped unless you have 15 or less life.
{T}: Add {W} or {U}.

When Sadistic Indulgence enters, create three 1/1 white Human creature tokens with “This creature can't attack or block.”
Pay 1 life: Destroy target nonland permanent you control.

Codex — Unraveling; Unraveling; Unrelenting; Unrelenting; Mindrip; Swipe Secrets. (As this enters, conjure its contents into a shuffled face-up additional library.)
Flash
When Mei's Collection enters, draw a card from its codex.

Activated abilities of cards in your hand cost up to {1} less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever a creature an opponent controls dies, its controller discards a card and loses 1 life.
{1}{B}{B}, {T}, Sacrifice another creature: Destroy target creature.

Whenever Thicketkeeper perseveres, add {G}{G}. Until end of turn, you don't lose this mana as steps and phases end. (A creature perseveres when it survives damage.)

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Other artifacts you control have extort.
Whenever a spell you control resolves, if it was extorted three or more times, each opponent discards a card and you draw a card.

Whenever you cast a spell, harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)
Harmony — Yita, Almgrove Prodigy gains your choice of flying, first strike, vigilance, lifelink, hexproof, or haste until end of turn.

Choose one or both —
• Put a +1/+1 counter on each of up to two target creatures.
• Put a +1/+1 counter on up to one target Elemental and up to one target Soldier.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{2}{R}{R}: If an instant or sorcery source you control would deal damage to a permanent or player this turn, it deals that much damage plus 2 instead.

Flying
Long-Finned Skywhale can block only creatures with flying.

Hexproof
Whenever attackers are declared, the active player may pay {2} for each creature attacking you. Then you may have Bridge Kalak become an X/X Troll creature until end of turn, where X is the number of times that player didn't pay mana this way.

Flying
At the beginning of your end step, untap another target creature you control.

{T}: Draw a card, then discard a card.
Whenever you cast an instant or sorcery spell, untap Exchange Scholar.

Untrekked Territory enters tapped.
{T}: Add {B} or {G}.
When Untrekked Territory enters, you may put a loyalty counter on a planeswalker you control.

{1}{W}: Aegis Champion gains indestructible until end of turn.

Discard your hand, then draw two cards for each land card discarded this way. For each opponent, Marzen's Frenzy deals damage to that player or a planeswalker they control equal to twice the number of instant or sorcery cards discarded this way.

Target attacking creature gets +3/+3 until end of turn. If it's an artifact creature, it gains trample until end of turn.

Target creature gets +3/-3 until end of turn.
Kindle 3—{B}{R}, Pay 3 life. ({B}{R}, Pay 3 life, Exile this card from your graveyard: Create three 1/1 colorless Elemental creature tokens. Kindle only as a sorcery.)

Escalate {2} (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Search your library for a card, put it into your hand, then shuffle.
• Return target card from your graveyard to your hand.
• Add {B}{B}{G}{G}.

{T}: Add {C}.
{7}: Transplanted Citadel becomes a 6/6 Golem artifact creature until end of turn. It's still a land. This ability costs {1} less to activate for each artifact you control.

At the beginning of each end step, if a creature you control died this turn, each opponent loses 2 life.
{3}{B}: Target creature you control gains lifelink until end of turn.

{T}: Add {C}.
{T}: Each opponent may draw a card. For each player who does, draw a card.