I can’t think of I, Q and X
I had to stretch to include K and U

Adele
Bush, Kate
Cave, Nick
Dylan, Bob
Eno, Brian
Finn, Neil
Gabriel, Peter
Harvey, PJ
I???
Jackson, Joe
Kondo, Koji (lack of options, he wrote tunes for Mario series)
Levy, Hank
Mingus, Charles
Nelson, Willie
Oldfield, Mike
Presley, Elvis
Q??
Richard, Little
Springsteen, Bruce
Tharpe, Rosetta
Uehara, Hiromi (I like one album)
Vincent, St
Wonder, Stevie
X?????
Young, Neil
Zappa, Frank