msem-instigator

When Keepsake of Binding enters, exile target creature an opponent controls until Keepsake of Binding leaves the battlefield.
{4}, {T}: Tap target creature with power less than the exiled card's power.

{T}: Add {C}.
{T}: Add {C}{C}. Spend this mana only to cast artifact spells. Activate only if you control three or more artifacts.

Enchant player
At the beginning of enchanted player's upkeep, that player chooses draw step, main phase, or combat phase. They skip each instance of the chosen step or phase this turn.

Equipped creature gets +3/+2.
Equip enchantment creature {1}
Equip artifact creature {2}
Equip {3}

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
{5}: Unlock Key to the Nexus. If {W}{U}{B}{R}{G} was spent to activate this ability, you may cast the revealed card without paying its mana cost. Otherwise, put that card on top of your library.

Double strike
At the beginning of your upkeep, if Kiboshi is equipped, put a +1/+1 counter on it.

{T}: Create a 1/1 colorless Servo artifact creature token.
{T}, Sacrifice an artifact: Killdrone Assembly Works deals 1 damage to any target.

[+1]: Choose up to one target creature. Until your next turn, whenever that creature attacks you or Kimar, Kimar deals 4 damage to that creature.
[–1]: Put a +1/+1 counter on target creature. That creature gains lifelink until end of turn.
[–7]: Search your library for a creature card and put it onto the battlefield. You gain life equal to its power. Then shuffle.

Kinsang Shrine enters tapped.
{T}: Add {B} or {G}.
{B/G}, {T}, Sacrifice Kinsang Shrine: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

When Kiri Yoroi enters, create a 2/2 colorless Spirit creature token and attach Kiri Yoroi to it.
Equipped creatures you control get +1/+1.
Equip {2}

Equipped creature gets +1/+2.
Whenever equipped creature deals combat damage, judge it. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)
Equip {2}

{T}: Add {R}.
{R}, {T}: Target creature gains haste until end of turn.

Krismite Shard enters tapped.
{1}, {T}, Sacrifice Krismite Shard: Aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

{T}: Add {C}.
When Krismite Vault is put into a graveyard from the battlefield, create a tapped colorless artifact token named Mox Krismite with “{T}: Add one mana of any color.”

{T}: Add {C}.
Tap an untapped creature you control: Kurayami Shrine becomes a 1/1 Spirit creature with deathtouch until end of turn. It's still a land.

Trample
{2/G}{2/G}, {T}: Put two +1/+1 counters on Laden Bruiser.

Laiyru Shrine enters tapped.
{T}: Add {G} or {U}.
{G/U}, {T}, Sacrifice Laiyru Shrine: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Whenever one or more creatures you control deal damage to a player, put a charge counter on Lake of Rage.
{T}: Add {C}.
{T}, Remove a charge counter from Lake of Rage: Add one mana of any color.

({T}: Add {W} or {U}.)
As Lakeside Park enters, you may pay {1}. If you don't, Lakeside Park enters tapped.

{T}: Add {R}.
Whenever you cast a spell from anywhere other than your hand, copy that spell. You may choose new targets for the copy.

{T}, Pay 1 life: Add {U} or {R}.
{2}, {T}, Sacrifice Lamplit Thoroughfare and another permanent: Draw a card. Activate only during your turn.

({T}: Add {B} or {R}.)
Lavatorn Fields enters tapped unless you control a basic Swamp or a basic Mountain.

Whenever equipped creature attacks, put a +1/+1 counter on it.
Equip {2}

As Legacy Foundations enters, you may reveal a Plains or Swamp card from your hand. If you don't, Legacy Foundations enters tapped.
{T}: Add {W} or {B}.

Enchant creature
Enchanted creature has “Whenever this creature attacks, attacking creatures you control get +1/+1 until end of turn.”