msem-instigator

Defender (This creature can't attack.)
{W}, {T}: You gain 1 life.

Rustshell Crustacean gets +1/+1 for each artifact you control.
Whenever Rustshell Crustacean attacks, choose one —
• Search your library for an Equipment card, reveal it, and put it into your hand, then shuffle.
• Create a Treasure token.

{7}, {T}, Sacrifice Samaki School: Look at the top four cards of your library. Put two into your hand and the rest on the bottom of your library in any order.

Haste
Sandstorm Sentinel enters with X +1/+1 counters on it, where X is your fealty to Deserts. (Each Desert you control counts toward your fealty to Deserts.)
Mirage {1}{R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Trample
{2}{R}: Santriza Arsonist gets +3/+0 until end of turn.

When Sasori Nightrunner enters, create a 2/2 colorless Spirit creature token.
Whenever a colorless creature you control dies, each opponent loses 1 life.

Trample
Savage Mammoth gets +1/+1 for each land you control.
Ride {4}{G} ({4}{G}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Schoolmaster gets +1/+1 for each other Merfolk you control.
When Schoolmaster enters, create a 1/1 white Merfolk creature token.

Scion of the Wild's power and toughness are each equal to the number of creatures you control.

Play with the top card of your library revealed.
You may cast Elemental spells from the top of your library.

Defender
{1}{U}: Sea Wall gets +0/+1 until end of turn.
Whenever Sea Wall perseveres, you may return target creature an opponent controls to its owner's hand. (A creature perseveres when it survives damage.)

When Seeker of Communions enters, choose target player. If that player is poisoned, draw a card. Otherwise, that player gets a poison counter.

When Seishin Smokeshaper enters, create a 2/2 colorless Spirit creature token.
Whenever you cast a noncreature spell, colorless creatures you control get +1/+1 until end of turn.

When Seishin Tidekeeper enters, create a 2/2 colorless Spirit creature token.
Colorless creatures you control have flying.

Trample
Ser Malcomn's power and toughness are each equal to the number of nonbasic lands your opponents control.

When Serene Initiate enters, rouse 1. (Put a +1/+1 counter on a permanent you control. If it isn't a creature, tap it and it becomes a 0/0 creature in addition to its other types.)
{3}{G}{G}: Creatures you control get +2/+2 and gain trample until end of turn.

When Servant of Armageddon dies, destroy all creatures.

Whenever an artifact is put into your graveyard from the battlefield, you may draw a card. If you do, discard a card.
{T}, Exile three noncreature cards from your graveyard: Create a 1/1 colorless Construct artifact creature token.

Pressure {2}{G}{G} (You may cast this spell for its pressure cost if there are seven or more cards in your graveyard.)
Trample, hexproof
Shambling Dreadreef's power and toughness are each equal to the total number of land cards you own on the battlefield and in your graveyard.

Shambling Hive power and toughness are each equal to the number of Insects you control.
Shambling Hive has vigilance as long as you control four or more Insects, and has trample as long as you control eight or more Insects.

You may have Shaper of the Formless enter as a copy of any creature on the battlefield, except it has “{2}{U}: Target face-down creature becomes a copy of this creature until end of turn. Turn that creature face up. At the beginning of the next cleanup step, turn it face down.”

Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)

Concord — {T}: Tap target nonland permanent. Activate only if there are four or more card types among permanents you control.

Other creatures you control get +0/+1.
Whenever a creature you control perseveres, you gain 1 life. (A creature perseveres when it survives damage.)

Prowess
{1}: Shifting Dweller gets +1/-1 until end of turn.