The Walls of Ba Sing Se

Firebending 2 (Whenever this creature attacks, add RR. This mana lasts until end of combat.) Whenever you cast a spell while Fire Lord Azula is attacking, copy that spell. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Menace, prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) Other Allies you control have menace and prowess. Whenever you cast a noncreature spell, create a 1/1 white Ally creature token.

Firebending 2 (Whenever this creature attacks, add RR. This mana lasts until end of combat.) When Azula enters, target opponent exiles a nontoken creature they control, then they exile a nonland card from their graveyard. During your turn, you may cast cards exiled with Azula and you may cast them as though they had flash. Mana of any type can be spent to cast those spells.

This land enters tapped unless you control a basic land. T: Add R. 1R, T: Target creature you control gains firebending 4 until end of turn. (Whenever it attacks, add RRRR. This mana lasts until end of combat.)

This creature gets +1/+0 for each color among Allies you control. 2WUBRG: Earthbend 5. (Target land you control becomes a 0/0 creature with haste that's still a land. Put five +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped.)

As an additional cost to cast this spell, you may waterbend 6. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for 1.) Draw two cards. If this spell's additional cost was paid, instead shuffle your graveyard into your library, draw seven cards, and you have no maximum hand size for the rest of the game. Exile Spirit Water Revival.

1, T: Scry 2. Whenever you scry or surveil, look at the top card of your library. You may cast that card without paying its mana cost. Do this only once each turn. (Look at the card after you scry or surveil.)

Each creature with mana value X or less loses all abilities until end of turn. Destroy those creatures.