msem-instigator

Rice Fields enters tapped.
{T}: Add {W} or {U}.
When Rice Fields enters, you may put a loyalty counter on a planeswalker you control.

{T}, Sacrifice Rickety Guildhall: Search your library for a Forest or Island card and put it onto the battlefield tapped, then shuffle.

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}: If you control ten or more nonland permanents, unlock Riddle of Entropy.
As long as the revealed card is a permanent card, each nonland permanent you own is a copy of it.

Equipped creature gets +2/+2 and has reach and protection from enchantment creatures. (It can't be blocked, targeted, or dealt damage by enchantment creatures.)
Equip {3}

Target creature you control and each other creature with the same name as that creature get +3/+3 and gain trample until end of turn.

Whenever you cast a creature spell or create a creature token, you may exile target creature you control. Return it to the battlefield under its owner's control at the beginning of the next end step.

Whenever you cast a nonblue spell, create a 1/0 blue Horse Nymph creature token.
Horses get +1/+1 and have flying.

This spell costs {1} less to cast for each artifact and enchantment you control.
Reveal the top seven cards of your library. Put any number of noncreature, nonland cards from among them into your hand and the rest of the revealed cards into your graveyard.

Copy target instant or sorcery spell you control. You may choose new targets for the copy.(Cast a copy of this spell once while this creature is on the battlefield.)

Primal {R} (During your turn, you may cast this spell for {R} instead of playing a land.)
Target creature gets +4/+0 and gains trample until end of turn.

Target creature gets -2/-2 until end of turn.
{3}{B}, Exile Rift Splicing from your graveyard: Aetherize target creature card with mana value 3 or less in a graveyard. Activate only as a sorcery. (To aetherize, create a token that's a copy of it, then exile that token.)

{T}: Add {C}.
{3}, {T}: Add {C} for each basic land you control.

Riga's Workshop enters tapped.
When Riga's Workshop enters, you may mill two cards.
{T}: Add {U} or {R}.

Enchant creature
Enchanted creature has “At the beginning of each player's end step, that player chooses another creature they control. That creature fights enchanted creature.”

Whenever you cast a storied spell, you may pay {1}. If you do, draw a card. (Enchantments and legendary spells are storied.)
Sacrifice Right to Rule: Storied permanents you control gain indestructible until end of turn.

If you control a Mountain, you may sacrifice an Aura rather than pay this spell's mana cost.
Righteous Bolt deals 2 damage to any target.

Target creature you control gets +2/+2 and gains lifelink until end of turn. It fights up to one target creature you don't control.

Put a +1/+1 counter on up to one target creature.
Draw a card.

Scry 1, then you draw a card and you lose 1 life.

Riko's Academy enters tapped.
When Riko's Academy enters, you may mill two cards.
{T}: Add {R} or {W}.

{T}: Exile target creature you control.
{2}, {T}: Target creature you control becomes a copy of a card exiled with Ring of Remembrance until end of turn.
{4}, {T}, Sacrifice Ring of Remembrance: Each creature becomes a copy of a card exiled with Ring of Remembrance until end of turn.

As long as equipped creature has power 3 or less, it can't be blocked and it can't be the target of spells and abilities you don't control.
Equip {1}
Whenever Ring of Souls becomes attached to a creature, an opponent of your choice may create a 2/2 black Spirit creature token.

{T}: Add one mana of any color. Activate only if you control a multicolored permanent or there is a multicolored card in your graveyard.

Foretell {2}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Attacking creatures get +2/+0 until end of turn. If this spell was foretold, those creatures also gain trample until end of turn.

Choose one —
• Rip Apart deals 3 damage to target creature or planeswalker.
• Destroy target artifact or enchantment.