msem-instigator

[+1]: Whenever a creature you control attacks this turn, Aleryn, Dungeon Disabler deals 1 damage to the defending player.
[–1]: Add X mana in any combination of {R} and/or {G}, where X is the number of creatures you control.
[–6]: You get an emblem with “Whenever a player casts a spell, this emblem deals 3 damage to any target.”

Whenever a land enters the battlefield under your control, create a 1/1 red Elemental creature token. Then if you control three or more Elementals, exile Aleryn, Trapseeker, then return him to the battlefield transformed under his owner's control.

Aleud Beastmaster has frenzy X, where X is the number of unblocked attacking creatures you control. (Whenever it attacks and isn't blocked, it gets +X/+0 until end of turn.)

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Aleud Bladedancer has hexproof as long as it's attacking.

Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)
Whenever Aleud Blademaster becomes blocked, it gains double strike until end of turn.

Enchant creature
Enchanted creature gets +2/+2 and has hexproof.
Sacrifice Aleud Grace: Enchanted creature gains indestructible until end of turn.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Whenever Aleud Pathfinder becomes blocked, untap up to two lands you control.

Aleud Scorn deals 3 damage to target creature.
At the beginning of your upkeep, you may exile Aleud Scorn from your graveyard. If you do, add {R}{R}.

Harmony — Warriors you control get +1/+0 and gain menace until end of turn.
Whenever Aleud Warcaller attacks, harmonize. (Trigger up to one harmony of a permanent you control.)

Menace
Whenever a creature blocks, put a -1/-1 counter on that creature at end of combat.
Creatures with -1/-1 counters on them can't block.

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Vanishing 2 (This permanent enters the battlefield with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a time counter is removed from All Who Wander, you gain 2 life and scry 1.

When All-Blossom Memorial enters the battlefield, scry 1.
Prismatic — Whenever you cast a multicolored spell, you gain 1 life.
{T}: Add one mana of any color.

If a creature would die this turn, exile it instead.
All-Consuming Fire deals 4 damage to each creature.

Alluring Rider must be blocked if able.
Attain {4}{G} ({4}{G}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Whenever Almgrove Bladesinger attacks, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Target creature can't block this turn.

Infamy 1 (Whenever this creature deals combat damage to a player, if it has no +1/+1 counters on it, put a +1/+1 counter on it and it becomes infamous.)
When Alpha Scout becomes infamous, create a 2/2 green Wolf creature token.

Trample
Whenever a creature attacks, Alpha Stag gets +2/+2 until end of turn.

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.”)

Alquyut Mount can't attack or block alone.

Double strike
Whenever an opponent casts a spell that targets you or a spell or permanent you control, Alrathan Outcast deals damage equal to twice its power to that player.
Alrathan Outcast gets +1/+1 for each Aura and Equipment you control.

{T}: Add one mana of any color. If you spend this mana to cast a face-down creature spell, you gain 2 life.

First mate—At least half the cards in your starting deck are lands. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Trample
{1}, Discard a land card: Put a +1/+1 counter on Alvarez. He deals 1 damage to any target.

Reach
Concord — Am'atambi's Fangs gets +1/+0 and has deathtouch as long as there are four or more card types among permanents you control.

Trample
Each creature you control with a counter on it has trample.