Phillip Phillips (Make this Place Your Home)
Steven Stevens (guitar player with Billy Idol)
Any others?
B. B. King
(A bit of a cheat, but there you are.)
Vinnie Vincent. Played with KISS for a millisecond in the 80s, IIRC.
Duran Duran?
For a triple , how about !!!
Incidentally, go ahead and try a Google search for “!!!” I knew there had to be a Wikipedia page about them, but no luck. I had to Google “band with three exclamation points.”
Those are not musicians, they are bands. The OP specifically asked about and offered as examples individuals.
Fun fact : Lisa Lisa and Cult Jam had a number one song, “Lost In Emotion,” that was immediately preceded as #1 by LL Cool J’s “I Need Love.”
Their initials are the same
Sylvain Sylvain!
He offered solo artists as examples, but did not specify that answers must be so rigidly policed. But I shall desist if so desired, quarrymaster.
Dave Davies of the Kinks.
Dee Dee Ramone
J.J. Cale
Robbie Robertson (although the lead guitarist of The Band was originally Jaime Robert Klegerman).
Jeffrey Hammond-Hammond (of Jethro Tull)
Stan Stanley was a big deal in Iowa in the '30s.
Pat Patrick played barisax with Sun Ra’s band for eons. His son Deval is now governor of Massachusetts.
Bruce Dickinson, best known as the singer for Iron Maiden, went by the stage name Bruce Bruce in his early days singing for Samson.