msem-instigator

Whenever Scavenger of the Old Bay deals combat damage to a player, draw a card.
Ride {1}{U} ({1}{U}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Scavenging Soldier has first strike as long as it's attacking.
Attain {3}{W} ({3}{W}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Double strike
Creatures you control have trample.
Excess noncombat damage that would be dealt by sources you control to permanents an opponent controls is dealt to that player instead.

Flying, haste
Ride {1}{R} ({1}{R}: Transform this and attach it to target creature you control without a Mount. Ride only as a sorcery.)

At the beginning of your upkeep, if six or more cards are in your graveyard, you may transform Scuttling Gnat.

Target creature gets +1/+1 and gains first strike until end of turn.
Fabled {3}{W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Creatures with power less than Seer of the Hunt's power can't block it.

Whenever you scry, draw a card.

Enchant player
At the beginning of enchanted player's upkeep, that player creates a 1/1 white Soldier creature token.

{T}: Add {C}.
{5}{R}{G}, {T}: Transform Settled Satrapy.

When Shapur, the Fifth Shah enters, exile target instant or sorcery card from your graveyard. Until end of turn, you may cast that card. If that spell would be put into a graveyard, exile it instead.
Monument {4}{R} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Flash
Unveil {3}{B}{G} ({3}{B}{G}: Transform this. Unveil only as a sorcery.)

Destroy target noncreature permanent.
Memento {5}{G}{G} (You may cast this from your graveyard for {5}{G}{G}. If you do, put it onto the battlefield transformed after it resolves. Exile it if it would leave the battlefield or not resolve.)

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Ward—Discard a card.
{B}{R}: Demigod — Draw a card, then discard a card. You may have each opponent sacrifice a nonland permanent with the same mana value as the discarded card.
{4}{B}{R}: God — Create two tokens that are copies of Shi Hou's back face.

Target player discards a card.
Monument {1}{B} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

When Shifty Squirrel enters, you gain 3 life.
Sacrifice a creature: Transform Shifty Squirrel.

When you unveil Shining Elementalist, creatures can't block this turn.

Flying, lifelink
Whenever Shioki, Imperial Heir attacks, exile any number of other target nonland permanents you control, then return those cards to the battlefield under their owner's control.

Equipped creature gets +2/+2 and has flying and lifelink.
When equipped creature deals combat damage to a player, unattach Shionoshio, Ocean's Vow, then transform it.
Equip {W}{U}
Shionoshio can be your commander.

Enchant creature you control
At the beginning of your upkeep, create a token that's a copy of enchanted creature.

Target creature gains hexproof until end of turn.
Monument {2}{U} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Whenever Shoreline Stormers deals damage to a player, draw a card.
{2}{U}: Target creature can't be blocked this turn.

{2}{U}: Target creature can't be blocked this turn.

Shroudmaker's Domain enters tapped.
{T}: Add {W}.

Vigilance
Whenever Sibling of All Elements attacks, it gains flying until end of turn if you control a creature with flying. The same is true for first strike, double strike, deathtouch, indestructible, lifelink, menace, and trample.