The color purple. No, not the book or the movie. Just the color.
The music of Paul Hardcastle (and/or The Jazzmasters, which is pretty much the same thing.) Particularly with vocals by Helen Rogers.
Like the OP, I wished more people had read Maze Agency by Mike W. Barr. It was a good whodunit comic series but since it was not published by either of the Big Two, hardly anyone knew about it. It lasted for about two glorious years. 
Browsing Amazon, I found that the series is being collected and volume 1 is already out 
Improv comedy. I’ve been involved with it off and on since 1988. The people who see it seem to really enjoy it, but the general trend is that more people are reliably onstage performing it than are in the audience watching it. ** Whose Line Is It Anyway** notwithstanding, it has never transferred to TV well.
The Barney Miller TV show. I thought it was very popular, but I’ve been waiting forever for Season 2 to come out on DVD, and nothing yet. I think Season 1 didn’t sell enough.
I love sorghum syrup, and I wish it were more popular just so it would be easier to find on store shelves.
You can sometimes get it with your breakfast at Cracker Barrel (if you specially request it), but I notice that even some Cracker Barrels don’t seem to have it these days.
Man, nothing beats a hot buttered biscuit with a little sorgum syrup.
Great series, especially because it featured art by the fantastic Adam Hughes (best known for covers, pin-ups, and sexy cheesecake girls) back when he could still turn out a monthly comic book.
As for me…
Tom Waits
Neko Case
The Dresden Dolls
Suspenders with suits
Fedoras
Vietnamese food (in the U.S.; outside of Vietnam)
New York style delis (outside of New York)