For many years, I've relied on a blog called The Stripper's Guide, written by Allan Holtz, for much of my information on very obscure and unknown comic strips. Most times, when I'm researching various comic strips or creators, things that I find there can generally also be found in at least one or two other places online. Unfortunately, in the case of Bob Kane, I must rely solely on the information from The Stripper's Guide, because it seems to be the only place on the open Internet that any solid information can be found on the newspaper comic strips he created.
Bob Kane was the artist and co-creator, along with Bill Finger, of the comic book character Batman. Kane drew the Batman newspaper strip for three years, starting in 1943, and that's fairly well known. While writers and artists behind comic books didn't always work on the newspaper strips with their characters in them, it wasn't unheard of. Certainly nothing about that is obscure or unexpected. Going a bit deeper, Kane also worked on some projects for other comic magazines, and also worked at the Eisner-Iger studio drawing various humor comics. While there, he created the Mickey Mouse rip-off Peter Pupp, among many other things. Still, there is plenty of fairly easy to find information to be had on those topics.
The obscurity comes with the non-Batman newspaper comic strips that Kane produced, or possibly produced.
Editor and Publisher, the newspaper industry magazine, used to publish a syndicate directory at the end of each year, listing features offered by syndicates to newspapers, though not necessarily that actually ran in newspapers. Kane is listed as a creator of a few features, namely "The Losers" and "The Aristocrats" for the Ledger Syndicate and a newspaper version of "Peter Pupp" which was apparently distrubuted by Eisner-Iger Associates. I couldn't find any evidence of their existence outside of these listings, and Allan at The Stripper's Guide hasn't found anything on them either. However, there is one other that he's listed as creating, called "The Little Major", that there is a small bit of information on.
Small, in this case, means next to nothing. The strip was distributed by the short-lived General Features Syndicate, which is an obscurity in itself. Editor and Publisher has little information on the syndicate besides its address, there's no evidence of it being well advertised in any way, and Kane himself never mentioned it or "The Little Major," even in his autobiography.
The reason for its obscurity, and for Kane never mentioning it, is probably due to the amount of material that Kane was producing at the same time. "The Little Major" ran for a year, from 1937 to 1938, at which point he was already quite busy working at the Eisner-Iger studio. Given that it seems the General Features Syndicate was obscure even in its time, it makes sense that "The Little Major" wouldn't get much notice. Then, just a year later, he and Finger created Batman, and that was obviously where most of his focus shifted.
"The Little Major" isn't really too bad of a comic strip, either. The gags are fairly forgettable, but the artwork is quite good. Kane's drawing style definitely lends itself to that kind of humor strip, and I think I actually like it better than his work on Batman.
For more information:
Bob Kane at Comiclopedia
General Features Syndicate at The Stripper's Guide
General Features Syndicate comic strip series at The Stripper's Guide