msem-instigator

Young Dragonheart gets +1/+0 and has first strike as long as you control a legendary creature.

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.)

Wanderlust — Whenever a land you control enters, if you control four or more differently named lands, create a 1/1 green Saproling creature token.

Whenever you cast an instant or sorcery spell, tap target creature an opponent controls.

Whenever a nontoken creature you control dies, create a 1/1 black Skeleton creature token.

Whenever you cast a cryptic spell, create a 1/1 white Human creature token with lifelink. (Artifacts, enchantments, and modal spells are cryptic.)

{T}, Pay 1 life: Add one mana of any color.

Flying
First strike (This creature deals combat damage before creatures without first strike.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Young Tempter enters, you draw a card and you lose 1 life.

Double strike, haste

Target creature gains haste and trample until end of turn.
Fabled {3}{R/G}{R/G} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Soldiercycling {2}{W} ({2}{W}, Discard this card: Search your library for a Soldier card, reveal it, and put it into your hand, then shuffle.)

Other Rebel creatures you control get +1/+0.
When Youthful Renegade enters, create a 1/1 white Rebel creature token.

You have hexproof.
Adorned — Youthful Savior has hexproof as long as it's equipped and/or enchanted.

Whenever you draw your second card each turn, put a +1/+1 counter on Youthful Tortoise.
Cycling {2} ({2}, Discard this card: Draw a card.)

Whenever Yri, the Daring Blade and exactly one other creature attack, Yri and that creature can't be blocked by creatures with mana value 3 or less this turn.

Whenever Yrodu, the Lotus Ablaze attacks, eight target permanents don't untap during their controller's next untap step.
Whenever Yrodu blocks a creature, destroy that creature at end of combat.

When Yron Bay Sentinel enters, draw a card.

Flying, vigilance
If a nonland permanent entering the battlefield would cause a triggered ability of a permanent you control to trigger, you may have that ability trigger an additional time. If you do, each opponent copies that ability and may choose new targets for the copies.

Flying
At the beginning of combat on your turn, choose one —
• Other creatures you control gain flying until end of turn.
• Other creatures you control with flying get +2/+2 until end of turn.

Flying
When Yujei enters, create a 1/1 white Bird creature token with flying.
{2}{W}: Put a +1/+1 counter on another target creature. It gains flying until end of turn. If it already has flying, put a +1/+1 counter on Yujei instead.

[+1]: Up to one target creature gets +1/+1 and gains first strike until your next turn.
[+1]: Choose a player or planeswalker other than Yuno Moonchaser. Creatures can't attack that player or planeswalker until your next turn.
[0]: Move any number of loyalty counters from Yuno onto target planeswalker.

Double the number of each kind of counter on any number of target permanents.

Archive 2 (As this enters, shuffle the top two cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, target creature you control gains vigilance and indestructible until end of turn.

Whenever you cast a noncreature spell, look at the top X cards of your library, where X is that spell's mana value. Put those cards on top of your library in any order.