I came across an interesting article of ten songs heard regularly on radio, that never were in the top 40.  This is an American article and two of the songs listed actually were hits in Canada.  One reached number one, and it will be obvious which one, and another was from a well known British 60's band had a number three hit in Canada in 1965 but had no impact in the US.

Yet all of these songs are regularly heard today mostly on classic rock stations.  A few of them were never released as a single.. List and article is from Old School Shirts. https://oldschoolshirts.com/blogs/news/10-hit-songs-that-werent-actually-hits