The Walls of Ba Sing Se

Defender
Other permanents you control have indestructible.

Mirrorworks

Whenever another nontoken artifact you control enters, you may pay {2}. If you do, create a token that's a copy of that artifact.

Mountain

Island

Infinite Guideline Station

When Infinite Guideline Station enters, create a tapped 2/2 colorless Robot artifact creature token for each multicolored permanent you control.
Station (Tap another creature you control: Put charge counters equal to its power on this Spacecraft. Station only as a sorcery. It's an artifact creature at 12+.)
STATION 12+
Flying
Whenever Infinite Guideline Station attacks, draw a card for each multicolored permanent you control.

Sol Ring

Fishing Gear

Whenever equipped creature deals combat damage to a player, exile the top card of that player's library. If it's a permanent card, you may put it onto the battlefield under your control. If you don't, create a 1/1 blue Fish creature token.
Equip {2}

Naked Singularity

Cumulative upkeep {3} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
If tapped for mana, Plains produce {R}, Islands produce {G}, Swamps produce {W}, Mountains produce {U}, and Forests produce {B} instead of any other type.

Forest

Plains

Swamp

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Door to Nothingness

This artifact enters tapped.
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice this artifact: Target player loses the game.

Ramos, Dragon Engine

Flying
Whenever you cast a spell, put a +1/+1 counter on Ramos for each of that spell's colors.
Remove five +1/+1 counters from Ramos: Add {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}. Activate only once each turn.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Fellwar Stone

The Eternity Elevator

{T}: Add {C}{C}{C}.
Station (Tap another creature you control: Put charge counters equal to its power on this Spacecraft. Station only as a sorcery.)
STATION 20+
{T}: Add X mana of any one color, where X is the number of charge counters on The Eternity Elevator.

Dingus Staff

Whenever a creature dies, this artifact deals 2 damage to that creature's controller.

The Peregrine Dynamo

Haste
{1}, {T}: Copy target activated or triggered ability you control from another legendary source that's not a commander. You may choose new targets for the copy. (Mana abilities can't be targeted.)