How about Willie Walker, the Black Racer? And Jake Jordan, the Manhattan Guardian? Plus you’ve arguably got Pluto Parulian and Pericles Parulian, the first and second Doctor Permafrost – and, I’m guessing, Vince Velcro.
More people I’ve never heard of.
Superman’s mermaid girlfriend, Lori Lemaris.
I’d heard it was because the name “Bruce” was associated with homosexuals, in the way that “Rastus” was for black men, or “Paddy” for the Irish. I remember around that time a series of jokes involving two gay men named “Charles” and “Bruce”–lisped, of course.
I’m just now reading Super Boys, by Brad Ricca, a biography of Siegel and Shuster. The name “Jor-L” is actually recycled from some of their pre-Superman work.
And, truth be told, Siegel was heavy on recycling his work and that of others.
That’s according to Lou Ferrigno, and he says the network insisted on the name change, and since it was the 70s, there may have been a grain of truth to it. Kenneth Johnson, the producer, also says he named the character after his son David. All of those explanations may be true to some extent.
I remember the MAD Magazine parody, “The Incredible Bulk” which raised this issue. A TV is shown with Olympic gold medal winner Bruce Jenner and an announcer is heard saying, “And Jenner wins the decathlon! BRUCE IS THE GREATEST ATHLETE IN THE WORLD!”
Darrel Dane was a Quality character originally. But DC had Dane Dorrance and Cave Carson in the 1960’s.
So it isn’t just Stan. Though apparently Dr Banner’s name being Robert Bruce Banner is a nod to Stan getting confused and calling him “Bob Banner” once.
http://goodcomics.comicbookresources.com/2005/11/03/comic-book-urban-legends-revealed-23/
Of course, one should expect some number of names (at least 1/26, but probably more, given name frequencies) to be alliterative. So just throwing out examples doesn’t mean much, unless you also say how big a pool you’re drawing from.
Right. Well, there are other names, but it is a trope of the form, and recognized as such.
Let’s see, other names that aren’t alliterative (DC):
Rex Mason, Barry Allen, Ralph (and Sue) Dibny, Ray Palmer, Arthur Curry, Jefferson Pierce, Oliver Queen, Diana Prince, Gar Logan.
Linda Danvers and Dinah Lance have clearly swapped last names. 
(Actually, those are aversions: Dinah Lance is, depending on the version, Larry Lance’s widow, née Dinah Drake, or their daughter Dinah Jr. [Or sort of a little of both, for about three embarrassing years in the 1980s.] And “Linda Danvers” was a way to get Supergirl out of the L.L. club.)
June Moone - that’s rhyming
Johnny Thunder, Cliff Steele, Johnny Double - another sort of comic book name
Eel O’Brian - I don’t even know what’s up with that. (OK, he’s originally from Quality. Still, what?)
Ellie Elle El-Bob El.
And Bruce Wayne, and Dick Grayson, and Jason Todd, and Tim Drake, and Stephanie Brown, and Damien Wayne, and Barbara Gordon, and Selina Kyle, and Ra’s and Talia al-Ghul, and Harleen Quinzel, and Alan Scott, and Hal Jordan, and John Stewart, and Kyle Rayner, and Jimmy Olsen, and Perry White. That’s 17 names right there, that I thought of just on the basis of “well-known DC comics characters that haven’t yet been named in the thread”, and the only one I had to skip over was Guy Gardner. One alliterative name out of 18 seems pretty reasonable for what you’d expect from “no pattern”. And if you’re going to dig far enough to get characters like The Other Waldo Pepper was listing, then you’ve also got to list all of the characters of that level of prominence, and I’m sure there are tons of them.
Fair enough, but that cuts both ways: the post I was replying to asserted that the ‘alliterative names’ thing “is less a comic book thing than a Marvel thing.” Can’t we just as easily point to well-known Marvelites like Tony Stark and Steve Rogers and Charles Xavier and Johnny Storm and Ororo Munroe and Ben Grimm and Jean Grey and Nick Fury and Henry Pym and Janet van Dyne and Richard Fisk and Donald Blake and Hank McCoy and Bobby Drake and Clint Barton and Natasha Romanoff and Frank Castle and et cetera?
His real name’s Patrick: his criminal buddies nicknamed him “the Eel” because he was so slippery, he never got caught.
I say “real”… I mean real in the fictional setting of the comic. The name he was supposedly given as a fictional child, rather than the concocted nickname he’s imagined to have acquired as an entirely made-up adult.
Sure you can…when they outnumber the Peter Parkers, JJ Jamesons, Bruce Banners, Matt Murdochs, Dum Dum Dugans, Pepper Pottses, and so on 20 to one, and you summon the ghost of Julie Schwartz and get him to admit to doing it deliberately because he couldn’t remember the names otherwise, as Stan Lee has.
TBBT: Season 3, Episode 16 “The Excelsior Acquisition”:
"Raj: Bruce Banner, Reed Richards, Sue Storm, Stephen Strange, Otto Octavius, Silver Surfer, Peter Parker, oh, and worst of all, J. Jonah Jameson, Jr.
…
Raj: Hey, I didn’t even mention Dum Dum Dugan or Green Goblin, Matt Murdock, Pepper Potts, Victor Von Doom, oh, and worst of all, Millie the Model.
…
Raj: Fantastic Four, Daredevil, Invincible Iron Man, Happy Hogan, Curt Connors…
…
Raj: And worst of all, Fin Fang Foom."
But for me, the worst is Flick Falcon.