Songs that sound suspiciously similar to much more popular songs that were released shortly afterwards. This band toured with Led Zep: https://www.youtube.com/watch?v=beg6uNekcqI
Whole lot of love was released in 1969 ! ( just realized you seem to infer zeppelin copied them ) not the other way round ?
The Zep song that most people think is related to this is "The immigrant song" (compare the french horn to the ay-ah-ahhhhh vocals) on Led Zeppelin III. That album and Lucifer's friend's album were both recorded in 1970, Zep's in October and LF's in November. the two bands had previously toured together, though. So it is plausible that one copied the other, but unproven. (One of them does have a well-documented history of plagiarism battles, of course)
I don't know...but it took me awhile to stop thinking that this song was not sung by Elvis whenever I heard it, and "SUSPICION" is in the words.... https://www.youtube.com/watch?v=TUe7dMi2uLA
This problem goes back for centuries. I always hear Beethoven's third piano concerto when I listen to the pirates of Penzance.