trying to be reasonable for the whole definition of these "one-hit wonders" ...absolutely CANNOT trust any of the sites that list one-hit wonders
some are obviously not one-hit wonders, but there are just wayyy too many you think seem ok ...but then if you check them out ...they skitter around the top 40 with another hit or two ...usually just one other.
some seem like they meet the technical aspect, but have just large a body of work (think album oriented groups) ...even though they only had one US top 40 hit.
1971 - These songs are typically listed across sites for 1971 One Hit Wonders
ex.) Layla - Derek and the Dominoes (1971) ...short-lived group, they only had one top 40 hit (Bell Bottom Blues barely cracked the Billboard Top 100). Did they fade away from public's consciousness ...no, and it's Eric Clapton for criminey sakes
ex.) I'd Love To Change The World - Ten Years After (1971) ...great song, I want it. It was their only song to crack the US Billboard Top 40 (3 others that didn't crack the top 60). But they were rock album stalwarts with 4 straight Top 20 albums and plenty more charting albums. Can't in good conscious call them a one-hit wonder.
ex.) Smiling Faces - The Undisputed Truth (1971) ...these guys were R&B mainstays with a ton of hits on the US R&B charts in the 70s but only cracked the top US Billboard 40 with this song. They did however hit the top 100 5 other times and bumped up against the Top 100 3 other times. With that deep a R&B catalog and that kind of crossover success ...can't call one-hit wonders by a long stretch.
12.22: Precious And Few - Climax (1971)
sappy and completely AM-styled. The kind of song I would have never dared to admit I liked meanwhile secretly singing it in my room when it came on the radio. Not my first choice as you see above, but I'm glad it made it.