msem-instigator

{U}, Sacrifice Seal of Insights: Look at the top four cards of your library. Put one into your hand and the rest on the bottom of your library in any order.

Whenever Trusted Comrade and at least one other creature attack, create a 1/1 white Soldier creature token that's tapped and attacking.

Once each turn, when one or more cards are put into an opponent's graveyard from their library, you may draw a card.

First strike
Ascend {1}{B} ({1}{B}: Exile this creature, then return it to the battlefield transformed. Ascend only as a sorcery.)

At the beginning of your end step, draw a card.
Whenever a creature deals combat damage to you, that creature's controller gains control of Ambition's Crown.

When Patient Herbology enters, rouse 2. (Distribute two +1/+1 counters among permanents you control. If they aren't creatures, tap them and they become 0/0 creatures in addition to their other types.)
Sacrifice Patient Herbology: Untap target land. You gain 2 life.

When Faithless Deserter enters, you may sacrifice a creature. If you do, each opponent sacrifices a creature.

Flash
Whenever Whimsical Dancer enters or is exerted, target creature gets +1/+0 and gains first strike until end of turn.
You may exert Whimsical Dancer as it attacks. (An exerted creature won't untap during your next untap step.)

Menace (This creature can't be blocked except by two or more creatures.)

Enchant creature you control
When Purphoros's Benefaction enters, scry 2.
Enchanted creature gets +1/+1 and has haste.

Vigilance, trample

Populate, then you gain 2 life. (Create a token that's a copy of a creature token you control.)

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
When Ophelia's Neophyte enters, you may have another target creature you control gain lifelink until end of turn.

Flying
Whenever Sandslinger attacks, you may tap target creature if you've gained life this turn.

Bleed {0} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Look at target player's hand.
Draw a card.

Cast this spell only if an opponent controls two or more nonwhite creatures or you control six or more lands.
Create X 1/1 white Bird creature tokens with flying. You gain X life.

Lifelink
Creatures can't be sacrificed.
{1}: Add {G}, {U}, or {R}. Spend this mana only to cast a Human spell.

Whenever you cast a white spell, target player loses 2 life and you gain 2 life.
Whenever you cast a green spell, put a +1/+1 counter on Corrupted Warlord.

Choose one —
• Draw seven cards.
• End the turn. (Exile all spells and abilities, including this. The player whose turn it is discards down to their max hand size. Damage wears off, and “this turn” and “until end of turn” effects end.)

When Vagabond of the Dunes enters, each opponent discards a card.
Whenever an opponent discards a card, put a +1/+1 counter on Vagabond of the Dunes.
Surpass {5}{B} ({5}{B}: Transform this creature. This costs {1} less to activate for each counter
on it. Activate only as a sorcery.)

Silver-Dawn Elder gets +2/+2 as long as you control five or more lands.
Revive—{2}{G}{G}, Discard a card. ({2}{G}{G}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever you cast a legendary spell, add a quest counter.
1 — Look at the top seven cards of your library. You may reveal up to two legendary cards from among them and put them into your hand. Put the rest on the bottom of your library in a random order.
2 — You gain 5 life.
3 — Destroy all nonlegendary creatures.

When Flame Ascetic enters, you may exile up to one instant card and up to one sorcery card from your graveyard. Put a +1/+1 counter on Flame Ascetic for each card exiled this way.

Each player mills three cards.
Draw a card.