Are there any musicians who only put out one album, or one really respected album (while the other albums were forgotten) who are still considered well respected musicians and not one hit wonders?
I was thinking Meat Loaf may fit that bill because until he did bat out of hell II his first bat out of hell album was what he was known for. Then again his album dead ringer sold several million worldwide, so that probably isn’t accurate.
By ‘good’, do you mean most popular (commercially successful)? “Good” is not an objective word. Arthur Brown had one very successful album and then faded from sight, except for fans of his music and other musicians that he worked with, who probably thought his other works were also good.
Guns n’ Roses.
There, I said it.
Alanis Morrisette. (don’t snark the respected part; she did well for herself)
Liz Phair cones to mind. Her second and third albums are okay, then I compketeky lose track of her after that, but Exile n Guyville is the only one I find myself listening to (and I listen to it fairly regularly.)
Googling “one album wonders” brings up some suggestions, though many of them are IMHO either too obscure, or disqualified because the musicians involved did release other albums, just not in that configuration. But Jeff Buckley, The La’s, and The Sex Pistols may be reasonable suggestions.
Oh, The Knack. Don’t get snarky with me on that one, either. Great, aggressive power pop.
Thudlow - good ones.
Blind Faith, of course.
The Spin Doctors – Pocket Full of Kryptonite
ooo: The Stone Roses
Derek and the Dominoes.
Leo Sayer’s first two albums are great and eclectic and very original.
As someone who LOVES Guns ‘n’ Roses, I have to… agree with you. 
Appetite for Destruction: an all-time classic album. If you own any GnR album, it should be this one.
GnR Lies: really just a compilation of 2 EPs.
Use Your Illusion I & II: some good material in there for sure, but certainly could have been condensed into a much tighter single disc (though opinions greatly vary on what would be included on that single disc).
“The Spaghetti Incident?”: just an album of covers. No original material at all.
Chinese Democracy: not even GnR as everyone besides Axl Rose is concerned.
Depending on your definition of “famous”, Jackson C. Frank certainly counts, and he was certainly massively respected and his songs have been covered many times.
Skip Spence only had one solo album, but was a member of both Jefferson Airplane and Moby Grape before that.
Robert Johnson lived before albums were a thing, but his total recordings only fill two CDs, and he’s one of the most famous and respected blues musicians. There’s a lot of early blues musicians who didn’t record a great deal, but it’s arguable how famous they are…
I think Mountain’s first album may qualify. Perhaps their second.
It’s A Beautiful Day
This, to me at least, is the perfect answer to the OP’s question. This wasn’t a case of an artist or band managing to release one great album among several duds. Their eponymous album was their sole major-label release, and it was incredible from start to finish. Almost 25 years later I still pull it up on Spotify every now and then, and it still amazes me.
There have been other La’s releases since then, but they’re essentially all remastered, repackaged, BBC sessions or demos and outtakes from this one. Every couple of years a rumor circulates about Lee Mavers reforming the band for a second album, but at this point it seems that anything they might do would only tarnish the perfection of the original (cf. The Stone Roses’ “Second Coming”).
Whether the band meets the “Famous, respected” qualification among the general populace is debatable, but for years afterward it was impossible to read anything from the alternative music press without finding a glowing reference or comparison to the album, the band or Mavers himself every other month.
The reputation of Love, and their leader, Arthur Lee, rests (not quite but almost) entirely on their brilliant third album “Forever Changes”. It is at 40 on Rolling Stone’s greatest rock albums list, but I would put it higher.
Great choice.
Super Session. Kooper, Bloomfield, and Stills recorded it in two days, then left.
Jeff Wayne’s Musical Version of War of the Worlds
Mike Oldfield’s Tubular Bells.
BRAAAAAP!
Does not fit the requirements of the OP.
My entry for the thread is Hermann Szobel. He wrote and recorded one album,; it is still considered genius today. He then disappeared off the face of the planet.
Spanky and Our Gang
Peter Frampton?
Frampton Comes Alive that’s the only one Peter Frampton is known for. The others albums went in the cut out bin.
I had more than more than my stomach full of that talk box gimmick. One album is all I could stand.
discography shows all the duds that didn’t chart.