msem-instigator

Create a 1/1 white Spirit creature token with flying. (Then exile this card. You may cast the artifact later from exile.)

Creatures you control get +2/+0 until end of turn.
Metamorph {1}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

(As this Discovery enters and after your draw step, add a progress counter. Stop after you've discovered.)
I, II — Look at the top five cards of your library. Put up to one creature card with mana value 2 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Discovery — At the beginning of combat on your turn, tap target creature an opponent controls.

When Third Legion Rider enters, if you control an embattled creature, tap target creature an opponent controls. It doesn't untap during its controller's next untap step. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Flash
When Threadspinner enters, untap each enchanted permanent you control. Enchanted creatures you control get +1/+1 until end of turn.

Thriving Heath enters tapped.
As Thriving Heath enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Each creature you control enters with an additional +1/+1 counter on it.
Each planeswalker you control enters with an additional loyalty counter on it.

Exile any number of target creatures and/or planeswalkers you control. You gain 1 life for each card exiled this way, then return them to the battlefield under your control.

Target creature gets +1/+1 for each creature you control and gains flying and vigilance until end of turn.

Flash
Whenever Thundermane Fox enters or attacks, target creature you control gains double strike until end of turn.

Whenever Tide Crasher attacks, if you control another Merfolk, tap target creature defending player controls.

Permanents you control gain indestructible until end of turn. Untap each creature you control.
Cycling {W} ({W}, Discard this card: Draw a card.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)

Enchant creature
When Til Death enters, exile target creature an opponent controls other than enchanted creature until Til Death leaves the battlefield.
Enchanted creature has defender.

Double strike (This creature deals both first-strike and regular combat damage.)
If three or more creatures are attacking you, you may cast Timely Commander as though it had flash.

If you have less life than an opponent, you gain 6 life. If you control fewer creatures than an opponent, create three 1/1 white Soldier creature tokens.

Tap target creature. If you control a Monk, draw a card. (Then exile this card. You may cast the creature later from exile.)

Flying, lifelink
When Timestream Sentinel enters, put two +1/+1 counters on each other creature named Timestream Sentinel you control.

Your opponents can't search libraries unless they pay {2}.
[+2]: If an opponent has more life than you, you gain 2 life.
[0]: If an opponent controls more creatures than you, you create two 1/1 white Gnome creature tokens.
[–4]: Search your library for a creature card with mana value 2, put it onto the battlefield, then shuffle.

Flying

Flash
Enchant creature
Enchanted creature gets +1/+1 and has first strike.

Search your library for an artifact card with mana value X, where X is 1 plus the greatest mana value among artifacts you control, reveal it, put it into your hand, then shuffle.
You may cast Tireless Endeavor from your graveyard by sacrificing an artifact in addition to paying its other costs.

Nonstoried creatures lose all abilities and have base power and toughness 1/1. (Enchantments and legendary permanents are storied.)

First strike
Noncreature spells with mana value 4 or greater cost {1} more to cast.