msem-instigator

({T}: Add {W} or {B}.)
Gloomcover Steppe enters tapped unless you control a basic Plains or a basic Swamp.

Put target creature card from a graveyard onto the battlefield under your control. If that card was put into that graveyard this turn, it enters with an additional +1/+1 counter on it.

When Goblin Arsonist dies, you may have it deal 1 damage to any target.

Prowess
{3}{R}, Sacrifice Goblin Experimenter: Return target sorcery card from your graveyard to your hand.

Whenever Goblin Raidleader attacks, create a 1/1 red Goblin creature token that's tapped and attacking.
{1}{R}: Other Goblins you control get +1/+0 until end of turn.

When Goblin Sniper dies, you may pay {R}. If you do, it deals 2 damage to target opponent or planeswalker.

Whenever you cast an instant or sorcery spell, target creature can't block this turn.

{T}: Target creature with power 2 or less can't be blocked this turn.

When Goblin Twinblades enters, create a 1/1 red Goblin creature token.

Target creature gets +2/+2 until end of turn. Whenever that creature deals combat damage to a player or planeswalker this turn, draw that many cards.

Haste (This creature can attack and {T} as soon as it comes under your control.)
Motivate 2 (When this creature enters, you may motivate target creature with less power than this by putting two +1/+1 counters on it.)

When Goriana Earthshaker enters, you may untap target land you control. It becomes a 3/3 Elemental creature with haste until end of turn. It's still a land.

Motivate 2 (When this creature enters, you may motivate target creature with less power than this by putting two +1/+1 counters on it.)
Each creature you control with a +1/+1 counter on it has trample.

Motivate 1 (When this creature enters, you may motivate target creature with less power than this by putting a +1/+1 counter on it.)
When Goriana Tactician enters, you may tap target creature.

Flash (You may cast this spell any time you could cast an instant.)
When Gorillas in the Mist enters, prevent all combat damage that other creatures would deal this turn.

Other Dryad creatures you control get +1/+1 and have hexproof.

Flash
If a +1/+1 counter would be put on another creature, that counter is put on Grafted Physician instead.

Equipped creature has “{2}, {T}: This creature deals 1 damage to any target.”
{4}: Untap equipped creature.
Equip {3}

When Grave Reaper enters, if it wasn't cast from your hand, it gets +1/+1 until end of turn.
Unearth {B} ({B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

As an additional cost to cast this spell, exile two cards from your graveyard with the same mana value.
Search your library for a card with the same mana value as the exiled cards, reveal it, put it into your hand, then shuffle.

You may have Graveborn Usurper enter as a copy of any creature card in a graveyard, except it has “{2}{U}{B}, Exile a creature card from a graveyard: Graveborn Usurper becomes a copy of the exiled card, except it has this ability.”

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Griffin Skycaller enters, target creature you control gets +1/+1 and gains flying until end of turn.

As Grim Bastion enters, you may pay 2 life. If you don't, Grim Bastion enters tapped.
{T}, Sacrifice Grim Bastion: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

Target player sacrifices a creature. Create a tapped 2/2 black Zombie creature token.