The Riddler is definately the best example of a obscure villain that finally gained popularity among fans due to the intervention of the 1960's tv show. Much more so than The Penguin I believe.
With The Penguin's origins, Kane claims Oswald's inspiration came from little penguins who appeared in print to advertise Kool cigarettes, and which also hawked them on radio with the insistent falsetto slogan, "Smoke Kooools! Smoke Kooools!"
While on the other hand, Batman co-creator Bill Finger claims that Penguin's inspiration came from the idea that emperor penguins reminded him of stuffy english gentlemen in tuxedos. Resulting in a caricature of an aristocratic type.
But of course, in his first appearance, Oswald was fatal much quicker than nicotine.
However, he subsequently calmed down, much like many of his peers (Joker especially), and became merely an ingenious thief who often used birds to help him in his crimes.
Obviously, a ludicrous figure composed of disparate elements, but The Penguin may have worked and struck some sort of cord with the readers due to the fact that he represented a privileged class that they might have resented. Of course the same charge could be hurled at Batman/Bruce Wayne as well, but Oswald deftly deflected whatever resentment the readers might have felt against the rich during the 1940s.
LOL
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