msem-instigator

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.)
When the fourth spell of a turn is cast, you may unlock Mirror Cipher. If the revealed card is an instant or sorcery card, cast it without paying its mana cost and copy it. You may choose new targets for the copy.

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.)
{1}, Sacrifice two Clues: Unlock Hall of Lost Histories and put the revealed card into your hand.

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.)
{1}, Discard two cards: Unlock Cryptic Fragment. If the revealed card is a basic land card, put it into your hand.

Each creature you control that's enchanted or is an enchantment gets +1/+1.
{2}{W}{W}: You may reveal an enchantment card you own from outside the game and put it into your hand.

Uncharted Haven enters tapped.
As Uncharted Haven enters, choose a color.
{T}: Add one mana of the chosen color.

Treacherous Den enters tapped.
{T}: Add {B} or {R}.
{2}{B}{R}, {T}, Sacrifice Treacherous Den: Draw a card.

Stunning Cascade enters tapped.
{T}: Add {U} or {R}.
{2}{U}{R}, {T}, Sacrifice Stunning Cascade: Draw a card.

Sheltered Haven enters tapped.
{T}: Add {G} or {W}.
{2}{G}{W}, {T}, Sacrifice Sheltered Haven: Draw a card.

Serpentine Woods enters tapped.
{T}: Add {B} or {G}.
{2}{B}{G}, {T}, Sacrifice Serpentine Woods: Draw a card.

Pristine Delta enters tapped.
{T}: Add {W} or {U}.
{2}{W}{U}, {T}, Sacrifice Pristine Delta: Draw a card.

Ominous Quag enters tapped.
{T}: Add {W} or {B}.
{2}{W}{B}, {T}, Sacrifice Ominous Quag: Draw a card.

Jagged Cairn enters tapped.
{T}: Add {R} or {G}.
{2}{R}{G}, {T}, Sacrifice Jagged Cairn: Draw a card.

Fortress Arena enters tapped.
{T}: Add {R} or {W}.
{2}{R}{W}, {T}, Sacrifice Fortress Arena: Draw a card.

Cryptic Reef enters tapped.
{T}: Add {G} or {U}.
{2}{G}{U}, {T}, Sacrifice Cryptic Reef: Draw a card.

{T}: Add {C}.
{T}, Sacrifice Cave of Pleonexia: Destroy target nonbasic land an opponent controls. You and that player each create a Treasure token. Activate only as a sorcery and only if that land's controller controls four or more lands. (A Treasure token is an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Abyssal Crypt enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}, {T}, Sacrifice Abyssal Crypt: Draw a card.

Equipped creature has “Whenever this creature attacks, you may sacrifice Torch of Phoenixfire. When you do, Torch of Phoenixfire deals 3 damage to any target.”
Equip {1}

Equipped creature gets +2/+2 and has ward {2} and “Whenever this creature attacks, draw a card, then you may put a land card from your hand onto the battlefield.”
Equip {2}

When Scrying Pool enters, scry 2.
{1}, {T}: Add one mana of any color.

As Protean Jar enters, choose a creature type.
Each creature you control of the chosen type enters with an additional +1/+1 counter on it.
{2}: If Protean Jar isn't a creature, it becomes a copy of target creature you control of the chosen type, except it has Protean Jar's other abilities. Activate only as a sorcery.

Deathtouch
When Necrodromos enters, put a +1/+1 counter on target creature.

Meletian Trireme can't be blocked by creatures with power 2 or less.
Whenever Meletian Trireme enters or deals combat damage to a player or planeswalker, scry 1, then draw a card.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

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.

Trample
{3}, Discard Gilded Ram: Draw a card, gain 2 life, and create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Flash
Flying