Ultraman was a Japanese import with some seriously cheezy monsters (okay, so the whole show was cheezy). Not many people seem to remember it now, maybe due to low distribution, but my friends and I all played Ultraman constantly when I was very young.
My other obscure favorite is The Mighty Heroes, an early Ralph Bakshi cartoon. It only ran for 21 episodes. At some point the series was released on VHS, and I found a bootleg DVD copy on eBay six or seven years ago. I watch it once every couple of years.
In 1987-1988, Ralph Bakshi revived Mighty Mouse in Mighty Mouse: The New Adventures. It contained a LOT of adult humor, and was very controversial as a result. It was axed halfway through the second season.
In one of the episodes, a villain stole all of the numbers in Mouseville. Mighty Mouse went to an accounting firm for help, and the accountants turned out to be The Mighty Heroes in retirement. The complete series is supposed to be out on DVD in January. I'd buy it for that one episode.