17 cards where the mana cost is greater than or equal to {X} and the mana value = 0 and it’s legal in Commander and the color identity ≤ U

Walking Ballista (Double Masters #306)
Stonecoil Serpent (Commander Masters #976)
Astral Cornucopia (Commander Anthology Volume II #172)
Hangarback Walker (Commander Masters #951)
Clown Car (Unfinity #186)
Endless One (Commander Masters #804)
Cryptic Trilobite (Commander 2020 #21)
Chalice of the Void (Masters 25 #222)
Orochi Hatchery (Commander 2015 #260)
Omarthis, Ghostfire Initiate (Commander Masters #708)
Ugin's Conjurant (War of the Spark #3)
Shifting Wall (Stronghold #140)
Engineered Explosives (Double Masters #252)
Sigil of Distinction (Shards of Alara #219)
Briber's Purse (Khans of Tarkir #217)
Chimeric Mass (Modern Masters 2015 #204)
Phyrexian Marauder (Visions #151)

Though this query has ended, its relics still slumber in New Argive.