msem-instigator

Exile up to three target creatures you control, then return those cards to the battlefield under your control tapped.

When Arcor-Staff Adherent enters the battlefield, you may remove all -1/-1 counters from target creature.

Attacking creatures you control get +1/+0 until end of turn.
Draw a card.

Wanderlust — When Ardent Explorers enters the battlefield, if you control four or more differently named lands, create a 1/1 Scout creature token that's all colors. That token gains haste until end of turn.

Kicker {1}{R} (You may pay an additional {1}{R} as you cast this spell.)
Attacking creatures get +2/+0 until end of turn. Those creatures also gain first strike until end of turn if this spell was kicked.

Arid Causeway enters the battlefield tapped unless you control another Desert.
{T}: Add {R} or {W}.

When Aridland Camaar enters the battlefield, create a 1/1 white Bird creature token with flying.

If a creature would leave the battlefield this turn, exile it instead.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, target player sacrifices a creature.

When Arisen Haploc enters the battlefield, return target creature card from a graveyard to its owner's hand.
Revive {5}{B}{B} ({5}{B}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Whenever Arisen Helix attacks, scry 2.
If Arisen Helix would die, exile it instead.

Whenever you cast a noncreature spell, each opponent loses 1 life.
{4}, Exile Arisen Psion from your graveyard: Draw a card.

When Arisen Troops dies, you may destroy target creature that was dealt damage this turn.

Aristocrat's Gallery enters tapped.
When Aristocrat's Gallery enters the battlefield, look at the top card of your library. You may put it into your graveyard.
{T}: Add {G} or {U}.

Target creature you control gets +2/+2 until end of turn. If it's attacking, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Whenever an artifact or enchantment enters the battlefield under your control, Armament Scavenger gets +1/+0 and gains trample until end of turn.

As long as Armed Vendor is enchanted or equipped, it gets +1/+0 and has menace.

Enchant creature (Target a creature as you cast this. This card enters the battlefield attached to that creature.)
Enchanted creature gets +2/+2.
{1}{G}: Regenerate enchanted creature.

Reach, vigilance

At the beginning of your end step, you may put a progress counter on Armored Transports.
[PROGRESS 1-2] Creatures you control get +0/+1.
[PROGRESS 3+] Creatures you control get +0/+1 and have vigilance.

When Armored Valiant enters the battlefield, creatures you control get +1/+1 until end of turn.

Prowess
When Arms Tinkerer enters the battlefield, choose one —
• Destroy target artifact.
• Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Lifelink
When Army's Suppliers enters the battlefield, recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

{T}: Add {G}.
{1}{G}, {T}: Return target land card from your graveyard to the battlefield tapped.

When Arpechian Groundskeeper enters the battlefield, rouse 1. (Put a +1/+1 counter on a permanent you control. If it isn't a creature, tap it and it becomes a 0/0 creature in addition to its other types.)
Remove a +1/+1 counter from Arpechian Groundskeeper: Draw a card.

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.