Yacatecuhtli: [Aztec Empire/Mexico] The Aztec god of travelling merchants.
Yankee Doodle Pigeon: [USA] Hanna & Barbera's secret agent pigeon.
Yellowjacket:
Yukio: [USA] Wild One, assassin/adventurer from Marvel Universe 616.
Yusef: [USA] The Blood S.C.R.E.A.M. operative Mosque from Broadway Comics.