There are a number of composers who are only known by the general classical listening audience for one piece. From some, it is deservedly the only piece that is known or regularly played by performers today, for others it unfairly casts into a shadow over other equally good (if not perhaps more significant) works by them.
Here I have listed examples that I can think of, as well as whether I have heard any other pieces by these composers. I am interested in whether other people know more & have heard more works by such composers?
Albinoni - Adagio (arr. Giazotto)
Who hasn't heard this, quite honestly. Albinoni provided the basis for this famous melody, which C20th scholar & composer Giazotto elaborated into a piece of music. I don't remember hearing anything else from either composer. I do have something by Albinoni on a Baroque album, but I can't say that it's equally memorable as "his" greatest hit (nothing wrong, of course, if a tune is not memorable though).
Bruch - Violin Concerto No. 1
This is definitely one of the most famous works in this genre, but outside of this Bruch is very much a nonentity to most classical listeners. I recently heard his youthful Piano Trio live in concert, as well as the Double Piano Concerto on radio. Both perhaps sounded too Brahmsian for their own good.
Clarke - Trumpet Voluntary
Outside of weddings, is this guy's music (any other pieces) actually played?
Dukas - The Sorcerer's Apprentice
Used in Disney's film Fantasia, this is one of the most famous pieces in the repertoire. It is pretty spectacular, and perhaps eclipses another work I know by him, a ballet called La Peri (which sounds a bit like a combination of the then current Russian & French styles). Very lush. Dukas was an absolute perfectionist, who destroyed much of his music, which is a pity judging from these two fine works.
Leoncavallo - "On with the Motley" (Vesti La Giubba) from I Pagliacci
Mascagni - Mama, quel vino e generoso from Cavarellia Rusticana
These are two of the most famous arias in all opera, but they eclipse all of the other operas these two very similar guys (in terms of style, anyway) wrote. I haven't heard anything else by Mascagni, but I have heard arias from Leoncavallo's La Boheme (apparently Leoncavallo gave Puccini the idea to write his own opera based on that story)
Litolff - Scherzo from Concerto Symphonique No. 4
It's been years since I heard this virtuosic piece on radio, but I have heard absolutely none of this guy's other music.
Orff - Carmina Burana
I have seen this live & it was pretty repetitive but spectacular nonetheless. I have read about some of his other cantatas and operas, but never heard any of them.
Reznicek - Donna Diana overture
This guy is very obscure, apart from this famous piece.
Rodrigo - Concerto de Aranjuez
One of the most famous concertos of the C20th, not least for being popularised by the likes of Miles Davis. I haven't heard anything else by him, have you?
Sinding - The Rustle of Spring
This is a very pretty, picture postcard or chocolate box piece. I wonder who has heard anything else by this guy, because I don't remember doing so.
Villa - Lobos - Bachianas Brasilieras No. 5 for soprano & 8 cellos
This is the one composer on the list whose other works I know the most about & I think they are quite good. He not only put Brazil, but the whole of South America on the musical map. He was a prolific composer in all genres, but not many people known him outside of this greatest hit. A pity, for he wrote some great music - apart from the other 8 Bachianas, the 12 or so Choros are excellent as well...
Warlock - Capriol Suite for strings
I love this piece, very bouncy & energetic, but haven't heard anything else by Warlock.
Widor - Toccata from Organ Symphony No. 5
This is a very popular organ work, which has been used in many weddings. But I do have more of this guy's works, and I think that he was a very fine composer (he wrote 10 organ symphonies in total). Another famous piece is his Marche Pontificale from the first symphony.