msem-instigator

Flying
Whenever one or more counters are put on a creature you control, Curio Siren gets +1/+0 until end of turn.

Whenever Deluge Crab perseveres, target opponent mills three cards. (A creature perseveres when it survives damage.)

When Demented Brainiac enters and at the beginning of your upkeep, each opponent mills two cards.
{U}, Sacrifice Demented Brainiac: Exile each opponent's graveyard. Until end of turn, you may cast instant and sorcery spells exiled this way, and you may spend mana as though it were mana of any color to cast them.

Hexproof
Rapport — Whenever Depths Stalker and at least one other creature you control become tapped, Depths Stalker gets +1/+0 until end of turn and can't be blocked this turn.

When Diligent Fishermen enters, look at the top four cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

{T}: Target creature gets -2/-0 until end of turn.

When Drownyard Scavenger enters, each player may return an instant or sorcery card from their graveyard to their hand.

Whenever you cast a spell with mana value 4 or greater, catalyze. (The next spell you cast this turn costs {1} less to cast.)

When Elder Prophesier enters, look at the top five cards of your library. You may reveal a Curse card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

When Entelan Savant enters, scry 2.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Until your next turn, target creature an opponent controls gets -1/-0.
[Lore III] Scry 2, then draw a card.

{1}{U}, {T}: Draw a card, then discard a card.

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.
Whenever you cast a glitched spell, scry 2.

Esper Shardseeker can't be blocked.
Plainscycling {1}, swampcycling {1} ({1}, Discard this card: Search your libary for a Plains or Swamp card, reveal it, put it into your hand, then shuffle.)

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

Flash
When Expedition Duo enters, if you cast an Adventure spell or a permanent you controlled explored this turn, draw a card.

{T}: Draw a card. Activate only if you created a token this turn.

Ward {2}
As long as you control six or more lands, Frondpond Errand-Runner gets +2/+0 and can't be blocked.

Flying
{T}: Add {C}. Spend this mana only to cast spells or activate abilities during an opponent's turn.

You may play enchantment spells from your graveyard if you haven't cast a spell with that name this turn.
At the beginning of your end step, choose up to one enchantment you control. Shuffle the rest into your library.

When Hand of Dominion enters, tap target creature an opponent controls. It doesn't untap during its controller's next untap step.
At the beginning of your upkeep, if your fealty to Islands is five or greater, transform Hand of Dominion. (Each Island you control counts towards your fealty to Islands.)

When Helicos Octopus enters, scry 1. If an opponent is cursed, scry 3 instead.

When Humble Archivist enters, you may return target instant or sorcery card from your graveyard to your hand. If you do, conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

When Imperial Artisan enters, draw three cards, then put two cards from your hand on top of your library in any order.

Prismatic — Whenever you cast a multicolored spell, target player mills two cards.