My favorites would be...
No Rain - Blind Melon
Counting Blue Cars (Tell Me All Your Thoughts On God) - Dishwalla
...most people probably have heard those two so I won't post links. The third one I don't think is necessarily a one-hit wonder because it wasn't exactly a hit song, but I think it counts because it's really the only song by this band anyone who's heard of them knows. They weren't a great band or anything, but this song is fantastic. It was my favorite for a long time... Really chill.
The Rock - Delakota
Delakota - The Rock - YouTube