Secret Lair Showcase Planes

Plane — Secret Lair

Change the text of each sorcery spell and sorcery card not on the stack by replacing "sorcery" with "instant."
Whenever chaos ensues, choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

Deceptive Divination

When you planeswalk to this plane and at the beginning of your upkeep, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")
Whenever chaos ensues, draw two cards, then discard two cards. Untap up to three lands.

Fblthp: Completely, Utterly, Totally Lost

Each creature's base power is equal to its printed toughness.
Each creature's base toughness is equal to its printed power.
Whenever chaos ensues, draw a card from the bottom of your library.

Finally! Left-Handed Magic Cards

At the beginning of each player's end step, if that player doesn't control a creature named Yargle, Glutton of Urborg, that player puts a bargle counter on a creature they control. It becomes a copy of Yargle, Glutton of Urborg, except it isn't legendary.
Whenever chaos ensues, choose Swords to Plowshares, Opt, Fatal Push, Anger of the Gods, or Explore at random. Copy the chosen card. You may cast the copy without paying its mana cost.

Happy Yargle Day!

Players may cast spells as though they were other cards legal in this game's format with the same type and mana cost. (Mana cost includes color.)
Whenever chaos ensues, exile cards from the top of your library until you reveal a nonland card. You may cast that card without paying its mana cost, but only as another card following this plane's first ability. Put the rest on the bottom of your library in a random order.

Imaginary Friends (Plane)

Legendary Food tokens you control have hexproof and indestructible.
When you planeswalk to this plane, create Li'l Giri, a legendary 1/1 colorless Food Warrior artifact creature token.
Whenever chaos ensues, put X +1/+1 counters on target legendary artifact creature you control, where X is the number of times you've rolled the planar die this turn.

Li'l Giri Saves the Day

Whenever a nontoken creature attacks, exile it. Return it to the battlefield under its owner's control tapped and attacking at the beginning of that player's next declare attackers step.
Whenever chaos ensues, goad target creature. (Until your next turn, It attacks each combat if able and attacks a player other than you if able.)

Math is for Blockers (Plane)

All permanents are artifacts in addition to their other types.
All cards that aren't on the battlefield, spells, and permanents are colorless.
Players may spend mana as though it were mana of any color.
Whenever chaos ensues, the next spell you cast this turn has affinity for artifacts.

Mycosynthwave

pLAnE — sECreT LaIR

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sAnS mERcY

At the beginning of each player's upkeep and whenever a player casts a spell, that player creates a 1/1 green Squirrel creature token.
Whenever chaos ensues, put a +1/+1 counter on each Squirrel you control.