msem-instigator

{1}{U}: Skysail Rigger voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Skysail Rigger phases in, put a flying counter on it.

Enchant player
Creatures enchanted player controls get -1/-0.
If Curse of the Banshee would be put into a graveyard from the battlefield, exile it instead.

Creatures with defender you control can attack as though they didn't have defender.
Each creature you control assigns combat damage equal to its toughness rather than its power.

If you would create a token, you may instead create a tapped 2/2 green Faerie Bard creature token.
Whenever one or more creature tokens you control deal combat damage to a player, that player sacrifices an artifact or enchantment.

At the beginning of your end step, return target creature card with mana value X or less from your graveyard to the battlefield with a finality counter on it, where X is the greatest number of creatures you control that share a creature type.

Whenever a permanent you control leaves the battlefield, Second-Day Slayings deals 1 damage to each opponent.

Flying
When Blackblood Feaster enters, you may have each player sacrifice a creature.
Pay 2 life: Blackblood Feaster gets +2/+2 until end of turn. Activate only once each turn.

Trample
Whenever a creature attacks, Alpha Stag gets +2/+2 until end of turn.

({T}: Add {U}.)
Aerie's Pillar enters tapped.
Flying
{2}{U}{U}: Aerie's Pillar becomes a creature in addition to its other types until end of turn.

Each player can't cast more than one spell each turn.
You may cast spells from your hand without paying their mana costs.

Prowess
When Adept of Signals enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Tokens you control have “{2}, {T}: Sacrifice this token: Draw a card.”

Desiccated Trail enters tapped unless you control another Desert.
{T}: Add {W} or {B}.

{T}: Look at the top and bottom card of your library. Put up to one on top of your library and the rest on the bottom in any order.
{2}: Mill a card.

This spell costs {2} less to cast for each face-down creature you control.
Flying

Whenever an Army you control dies, if it wasn't sacrificed, recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

When Smoldering Husk dies, it deals 2 damage to any target.
{2}{R}: Smoldering Husk gets +2/+0 until end of turn.

When Benthic Alchemist enters, draw a card, then discard a card, then mill a card.
Whenever you cast an instant or sorcery spell, create a 1/1 colorless Elemental creature token. It gains haste until end of turn.

Put target creature with power X or less on top of its owner's library.
Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Target creature gets +2/+0 and gains first strike until end of turn. If it's a Dragon, put a +1/+1 counter on it.

Choose one —
• Create a 3/3 red Shark enchantment creature token.
• Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

Once each turn, when you spend mana from a Desert to cast a spell, create a 1/1 red and green Bird creature token with flying and vigilance.
Whenever three or more creatures you control deal combat damage to a player, untap each land you control.

When Gharsha, Monstrous Quarry enters, each opponent creates a 1/1 green Elf creature token.
Whenever a creature you control becomes blocked, you may pay {1}. If you do, put a +1/+1 counter on that creature.

When Gilded Authority enters, create two Treasure tokens. (They're artifacts with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Creatures your opponents control get -1/-0.

Each other creature you control that's a Merfolk or an Elemental gets +1/+1.
Whenever you cast an instant, sorcery, or Merfolk spell, you may pay {1}. If you do, create a 1/0 blue Elemental creature token.

At the beginning of your end step, draw two cards and you lose 2 life.