10 cards where the cards are lands that produce three colors of mana

Arcane Sanctum (March of the Machine Commander #390)
Crumbling Necropolis (The Lost Caverns of Ixalan Commander #326)
Frontier Bivouac (Commander Masters #997)
Jungle Shrine (Outlaws of Thunder Junction Commander #303)
Mystic Monastery (Commander Masters #1014)
Nomad Outpost (Outlaws of Thunder Junction Commander #306)
Opulent Palace (Outlaws of Thunder Junction Commander #307)
Sandsteppe Citadel (Commander Masters #1024)
Savage Lands (Commander Masters #1025)
Seaside Citadel (Murders at Karlov Manor Commander #288)

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