The alphamegalog of the cities of Missouri lists the largest city in Missouri for each letter of the alphabet. In this case, ‘largest’ is based on population within the city proper.

Arnold
Blue Springs
Columbia
Darden Prairie
Excelsior Springs
Florissant
Gladstone
Hazelwood
Independence
Joplin
Kansas City
Lee’s Summit
Mehlville
Nixa
O’Fallon
Poplar Bluff
Queen City
Raytown
Saint Louis
Town and Country
University City
Valley Park
Wildwood
(no X)
(no Y)
Zalma