msem-instigator

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.

Secret Lagoon enters tapped. When it enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
{T}: Add {G} or {U}.

{T}, Sacrifice a creature: When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

{T}, Sacrifice a creature: Target player discards a card and loses 1 life. Activate only as a sorcery.

Mill four cards, then return a creature or enchantment card from your graveyard to you hand. You gain 3 life.

Serpentine Woods enters tapped.
{T}: Add {B} or {G}.
{2}{B}{G}, {T}, Sacrifice Serpentine Woods: Draw a card.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Serul Cove Escort encourages a creature, that creature gains flying until end of turn.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Mill two cards.
[Lore III] Return target creature card from your graveyard to your hand.

Equipped creature gets +2/+2 and has ward {2} and “Whenever this creature attacks, draw a card, then you may put a land card from your hand onto the battlefield.”
Equip {2}

Heroic — Whenever you cast a spell that targets Setessan Avenger, create a 1/1 green Nymph Dryad enchantment creature token with “{T}: Add {G}.”
Whenever Setessan Avenger deals combat damage to a player, untap all lands and Dryads you control.

When Severed Hands enters, surveil 2.
Whenever one or more cards leave your graveyard, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

When Shackled Memories enters, return target instant or sorcery card from your graveyard or card with flashback you own from exile to your hand.
Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, create a 1/1 white Spirit creature token with flying.

Lifelink
Each other artifact creature you control enters with an additional +1/+1 counter on it.

Flash
Flying
When Sharuum, Archmagocrat enters, return to the battlefield all nonlegendary artifact cards in your graveyard that were put there from the battlefield this turn.

Sheltered Haven enters tapped.
{T}: Add {G} or {W}.
{2}{G}{W}, {T}, Sacrifice Sheltered Haven: Draw a card.

Flying
When Shilgengar's Harvester enters, each opponent discards a card and loses 2 life.

Whenever you scry, put a +1/+1 counter on Shimmershell.

Return target creature card from your graveyard to the battlefield. Put a +1/+1 counter on it for each of its colors.

Flying, vigilance

Flying
When Sigarda's Shepherd enters, another target creature you control gets +1/+1 and gains indestructible until end of turn.

Flying
Other creatures you control enter with an additional +1/+1 counter on them.
If a spell or ability an opponent controls causes you to discard Sigarda, Dawn of Mercy, put it onto the battlefield instead of putting it into your graveyard.

First strike
Whenever Sighted-Caste Knight deals combat damage to a player, draw a card.

Untap target creature. It gets +2/+2 until end of turn.
Cycling {W} ({W}, Discard this card: Draw a card.)

Creature tokens you control get +1/+0.

Equipped creature has “{T}: Reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put it into your hand.”
Equip {2}