There has been a bit of a halo effect put over certain legacy acts. Since your music was good enough to have hanging around for all these years, it's almost understood that most of your material is to some degree decent. Even so, many artists still have those few albums that no one really remembers all that well.
As opposed to the certain gelling that happens on classic albums, these records were just at the wrong place at the wrong time. From having a cheap marketing ploy to go with it or just some random change of scenery, these albums were not given the proper time of day that they really should have gotten in their time. Does that mean that these are the undiscovered masterpieces of their catalog? No, not necessarily. In fact, most of these may be harder to get into on first listen if you consider yourself a fairweather fan of any of these acts.
On the other hand, these are the records that you start to appreciate more and more with each passing listen, almost like the tunes themselves are growing on you like some sort of sonic fungus. You might not have got it the first time, but these records will end up sticking with you whether you like it or not.
10. Young Americans - David Bowie
Only a few rockstars can have different eras within the confines of their career. Hell, most people looking to get famous are lucky enough if they have just one era of relevancy in the music industry. At the end of the '70s though, rock was changing and so was David Bowie.
After coming out of his glam rock period, the arrival of Diamond Dogs showed that the Starman was starting to get a little bit tired of the genre that brought him to superstardom. Once the landmark announcement of the death of Ziggy Stardust left everything ambiguous, Bowie's record Young Americans saw him answering the call of soul. Being inspired by the soul scene happening on the East Coast of America, most of this record is an unabashed homage to the soul influences, including drafting in future veterans like Luther Vandross to sing backup on here.
Aside from having some great cuts like the title track, the only reason this tends to get brought is the fact that it has John Lennon on it. During some downtime in New York, Bowie ran into Lennon in the same studio and then collaborated with him when making his next big hit Fame. Though this album is more of a relic from Bowie's '70s period, this at least showed us that Bowie was just beginning to flex his musical muscles.