I would think Rush would have to be the poster child for this. After 40 years and twenty-something albums, ask most people to name a song by Rush and I’ll bet the vast majority would say “Tom Sawyer” (maybe with “The Trees” coming in a distant second).
Are there any other bands that have put out so much material that are primarily known for one song?
Dutch prog rock band Focus released 13 albums, but is mainly known for Hocus Pocus.
Dutch band Golden Earring released 26 albums, had dozens of top10 hits in the Netherlands, but is internationally known only for Radar love (and possibly Twilight zone).
How about Chicago? 36 Studio albums, most albums sales of an US Band I believe but what songs can people name? I guess I sometimes hear “25 or 6 to 4”.
Blues Traveller. Known only for 'Runaround '.
You know, I thought about Golden Earring…
Good point about “Hocus Pocus” by Focus, except I wonder if most people who recognize the song could even name the band. 
Hocus Pocus by Focus is actually how I think of the song. But you might be right.
Probably not at the top of the list, but I bet most people would only be able to name “Aqualung” if you asked them to name a Jethro Tull song (of people even able to name one song).
I think of the Grateful Dead this way. It feels like you are either part of their world, and parse Robert Hunter lyrics while figuring out which bootlegs are the best, or you are like most folks, who simply know of this big, amorphous “music thing” known as the Grateful Dead, but couldn’t name a song if their life depended on it.
ETA: if you’re from that era, maybe their radio hit Touch of Grey, or the Casey Jones song.
Traffic. The only song you hear played is “The Low Spark of High-Heeled Boys” (and sometimes “Feelin’ Alright,” though cover versions are more common).
Bobby McFerrin – who has released a couple of dozen albums over the years – is only known for his novelty tune “Don’t Worry, Be Happy.”
I was going to say “Saturday in the Park” myself. Oddly, going by Billboard, do you know what their biggest single was? “Look Away” from 1988. I know that song, having just hit my teenaged tears at the time, but I had no idea until just now looking them up that it was by them.
ETA: sorry, its one of three number one hits. The others being “Hard to Say I’m Sorr,” and “If You Leave Me Now,” which I’m
Having difficulty conjuring up in my mind.
Actually, after listening to the other two Chicago hits, yeah, I totally know them, but would not have been able to name them offhand.
Gary Numan is incredibly prolific, but regarded as a one-hit-wonder who had a big single during the New Wave years.
I’m not sure how well-remembered they are, but…
Back in 1981 a Canadian pop-prog band called Saga had a top 40 hit in the US called “On the Loose.” Another minor hit was “Wind Him Up.” I think both are still played on the classic rock stations from time to time.
Those songs were from their fourth album. They’ve been around since 1978, and now have 22 studio albums and 8 live albums. They’re supposedly going to hang it up at the end of this year, but they’ve threatened this kind of thing before, so we’ll see.
Lou Reed probably qualifies - around 20 albums, and most only know him for “Walk on the Wild Side”.
I’d argue against Traffic - they really weren’t prolific, only releasing eight studio albums in the decade or so they existed. Plus “Dear Mr. Fantasy” is probably just as well known as “Low Spark”.
Frank Zappa might be in a similar boat with his novelty tune “Valley Girl,” except that I don’t think he’s known for that song so much as known for being an avant-garde musician. I suspect there are a lot of people who know who he is/was (and what he looks like) without being familiar with his music.
And yeah, I don’t think Chicago are one-hit-wondery enough to qualify.
Does anybody really know what one it is? Does anybody care? If so, I can’t imagine why; we’ve all got time enough to die…
I could probably name 100 Yes songs, but many people only know Roundabout.
I’d argue Owner of a Lonely Heart is just as well known.
Yeah, this is a pretty good one. Until well into college or maybe even to my mid-20s, while I knew of the Grateful Dead as a cultural phenomenon, the only song I ever could name by them was “Touch of Grey.” Especially odd, as I was into jam bands like Phish and Blue Traveler back then, just not the Dead. To this day, the only other Dead song I could name is “Sugar Magnolia” and that “Drivin’ the train, out of cocaine” sone, which, looking it up, is your aforementioned “Casey Jones.”
Lou Reed might be a good one, too. I suspect people would recognize “A Perfect Day,” but it’s hard for me to say. The Trainspotting soundtrack was around everywhere when I was in college, so it may just be a right place right time thing for me, and it’s not as well known in pop culture. “Sweet Jane,” too, but it’s also possible the Cowboy Junkies cover is more well known.
Looking it up, Gary Numan apparently has 22 albums to his name, but does anyone know anything but “Cars” by him?
What about Frank Zappa? 62 albums and only “Valley Girl” on the charts? Although it’s arguable that most people wouldn’t even be able to name that song.
ETA: ninja’d on Zappa.
ETA: Dammit. And ninja’d on Numan, too! WTH?
That’s the first Yes song that came to my mind. I would have to think a little bit to remember Roundabout (it’d be the tip-of-the-tongue song that I’d be struggling to remember. It’s probably as well known as Owner, but, for some reason, I just don’t think of it.) And beyond that, I got nuthin. I’ve listened to them here and there, but couldn’t name another song.