You forgot Brandy.
Jackee Harry, Sandra from 227, tried if for a while. Everybody just laughed.
Extra credit for alphabetization, to boot.
So did Janet Jackson. Same result.
Tito and La Toya fared better. Probably because their names were Tito and La Toya rather than Janet.
Esquerita - the performer who showed Little Richard how to do his job
Dion
Mickey (Baker) & Sylvia (Robinson) (Sylvia later made records under her first name)
Rosie (of “& The Originals”)
Ruby (of “& The Romantics”)
Paul & Paula
Peter, Paul & Mary
Sam & Dave
Ian & Sylvia
Lulu
Millie (Small, whose “My Boy Lollipop” was first issued under her first name. Later pressings added her last name.)
Sonny & Cher (she was already mentioned)
Dino, Desi & Billy
Peter & Gordon
Chad & Jeremy
Keith (“98.6”)
Sly (Stone)
Caleb (Quaye, made some records and guested on others’)
Derek (“Cinnamon”)
Melanie
Mel & Tim
Oliver (“Jean”, “Good Morning Starshine”)
Valdy (Canadian folk artist - short for Valdimir)
Lobo
Shirley (& Company - “Shame Shame Shame”)
Vangelis
Gowan
Nena
Pretty much any of those (Name) & (The Group) names would qualify, or not, depending on your criteria, so I left hundreds out!
Mako
Twiggy
Janet, if yore Nasty! Ahhh…YEAAAA!
I was too busy checking to make sure Rhianna and Rihanna were in fact two different women and I wasn’t going to embarass myself.
Fishbicycle, I don’t think some of the people you listed qualify. They may use their first name in their band’s name but they don’t use it personally. Sam & Dave, for example, called themselves Sam Moore and David Prater once they stepped off stage.
Yeah, well Sting’s mom calls him Gordon, and Liberace’s first name is Lee, so it doesn’t belong on the list. Sam Moore’s name is Sam and Dave Prater’s name is Dave. That’s what everybody called them in public and private. I’m not sure what nit you’re picking, or how it applies, really.
Houdini
Selena
Shakira
It’s like Sonny and Cher. Cher consistently goes by just her first name. Sonny, on the other hand, did not. He was generally known as Sonny Bono.
Or to use the example of Sam Moore. Here’s some of his albums: here, here, and here. As you can see he didn’t call himself just Sam professionally. And if you go to the wikipedia article on Sam Moore, you’ll find this quote from B. B. King: “To me, Sam Moore is the Frank Sinatra of Soul Music.” People use his last name.
Or if they were announcing a list of Grammy nominees, they might say “the nominees for best female vocalist are Christina Aguilera, Fiona Apple, Beyonce, Jewel, Sheryl Crow, and Madonna.”
If I said “Keef” would everyone know who I meant?
That’s Miz Jackson to you!
Yes you did, you left out “Tom and Jerry” though they later went the other way and recorded under their last names “Simon and Garfunkel.” (I don’t know who was who.)
Fabio
Emeril
Honus (Crossword answer Honus Wagner is the player on the rarest old baseball card. How many other Honus’s can you name 
)
Dr. Phil
Yan (of* Yan Can Cook*)
Ringo
Slash
Ichiro