msem-instigator

Disciple of Atemhar has lifelink as long as it has a +1/+1 counter on it.

When Elemental Loremaster enters, return an instant or sorcery card at random from your graveyard to your hand.

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle. Put a +1/+1 counter on each creature you control.

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Return up to two target cards from your graveyard to your hand. Exile Secret Stash.

When Climber's Outfit enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Equipped creature has reach.
Equip {1}

Until end of turn, target creature gets +1/+1 for each Equipment attached to it and gains flying and first strike.

Trample
Rubble Tender's power and toughness are each equal to the number of land cards in your graveyard.
At the beginning of your upkeep, sacrifice a land, then search your library for up to two land cards, put them onto the battlefield tapped, then shuffle.

Target creature gets +1/+0 and gains first strike until end of turn.
Target creature blocks this turn if able.

Poisonous 2 (Whenever this creature deals combat damage to a player, that player gets two poison counters.)
Sankataar Coilborn gets +1/+1 as long as an opponent is poisoned.

Add {R} and two mana of any one color.
When you next cast a spell this turn, Manifest Irrationality deals 3 damage to any target.

Mosecf, the Sunseeker's Path enters tapped.
Whenever a creature you control attacks, put a creation counter on Mosecf.
{T}, Remove ten creation counters from Mosecf and sacrifice it: Creatures you control get +2/+2 and gain vigilance until end of turn. Activate only as a sorcery.

{T}: Add {W} or {B}.
{W}{B}, {T}: Each opponent loses 1 life and you gain 1 life.

Create a token that's a copy of target creature you control.
Fabled {5}{U}{U} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Lifelink
When Stalked Healer enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

{B}, Remove a time counter from a permanent you control: Target player loses 1 life.

Enchant land
Enchanted land has “{T}: Add one mana of any color.”
{3}, Sacrifice Alpha Trial: Conjure a card named Test Run into your hand. (It's a sorcery that costs {X}{G} with “Create an X/X green Mutant creature token. Draw a card.”)

Whenever equipped creature attacks, put a progress counter on Astrina, Tempered by Glory.
Equip {1}
[PROGRESS 1-2] Equipped creature gets +1/+1 and has first strike.
[PROGRESS 3+] Equipped creature gets +4/+4 and has first strike and lifelink.

Defender
{T}: Scale-Crown Archer deals 1 damage to each opponent.
Prismatic — Whenever you cast a multicolored spell, untap Scale-Crown Archer.

Creatures you control gain trample until end of turn.
Draw a card.

This spell costs {1} less to cast if it targets a creature with power 3 or less.
Destroy target attacking or blocking creature.

First strike
Whenever an opponent casts a spell, Kiboshi's Guardian gains indestructible until end of turn.

Akimbo Slash deals 1 damage to each of up to two target creatures.
Ferocious — Those creatures can't block this turn if you control a creature with power 4 or greater.

Gain control of target noncreature, nonland permanent with mana value X.

At the beginning of your upkeep, each opponent mills two cards.
{3}{B}: Exile target nonland card from an opponent's graveyard. Copy it. You may cast the copy. Activate only as a sorcery. (You still pay its costs, including color. Copies of permanents enter as tokens.)

(Add a quest counter as this enters. Sacrifice after 3.)
1, 2 — At the beginning of your end step, if you cast no spells this turn, add a quest counter.
3 — Untap each creature you control. Until your next turn, they gain “{T}: Scry 1.”
Scry 2, then draw two cards. You gain 2 life.