msem-instigator

{T}: Add {C}.
{3}, {T}, Sacrifice City Gate: Put two +1/+1 counters on target creature you control that attacked this turn.

When Citywide Automation enters, create two 1/1 colorless Construct artifact creature tokens.
{2}{W}{W}, Sacrifice Citywide Automation: Creatures you control get +1/+1 until end of turn. Activate only as a sorcery.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

When Clairvoyant Mage enters, scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Whenever another creature you control enters, you gain 1 life.
{4}{W}: Return another target creature you control to its owner's hand.

Armed — Other Goblin creatures you control get +1/+1 and have haste as long as Clanleader of Beragnos is equipped.

Haste
Claret Gorger can't block.
Unveil {2}{B}{R} ({2}{B}{R}: Transform this. Unveil only as a sorcery.)

Whenever you cast an instant or sorcery spell, you may exile that card instead of putting it anywhere else as it resolves.
At the beginning of your upkeep, Clash Reactor deals X damage to each opponent, where X is the number of colors of cards exiled with Clash Reactor.

Flying
Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

Enchant creature
When Claustrophobia enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Whenever a creature enters under an opponent's control, you may have that player lose 1 life.
Unveil {2}{B}{R} ({2}{B}{R}: Transform this. Unveil only as a sorcery.)

When Clawing Shaman enters from your graveyard, you may exile it. If you do, return all creature cards from your graveyard to the battlefield.
{4}{B}{B}{B}, Sacrifice a creature: Return Clawing Shaman from your graveyard to the battlefield. Activate only as a sorcery.

Sacrifice a creature: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

This spell costs {1} less to cast for each creature you attacked with this turn. (Those creatures don't have to still be on the battlefield.)
Flying

{W}, {T}: Tap target creature.

{T}, Pay 1 life: Add {W} or {U}.
{1}, {T}, Sacrifice Cleared Vault: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Soldiers you control get +1/+1.
Whenever one or more creatures attack, create a 1/1 red Soldier creature token.

Whenever you cast an instant or sorcery spell, Clever Infiltrator gets +2/+0 until end of turn and can't be blocked this turn.

Cliffside Entrance enters tapped unless you have 15 or less life.
{T}: Add {R} or {W}.

Equipped creature has flying.
Equip {3}

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}

When Climbing the Oldest Mountain enters, draw a card, then choose a card name.
Whenever a creature you control with the chosen name deals combat damage to a player, put two +1/+1 counters on it.

Whenever you cast a noncreature spell, you may shuffle target card an opponent owns in exile into its owner's library.

Equipped creature has hexproof. (That creature can't be the target of spells or abilities your opponents control.)
Equip {0}