Oh, dang, that's a toughie.
I mean, I like Philyra, because she was not only the only nymph-goddess that Kronos cheated on Rhea with, but the mother of Chiron, by Kronos. Not to mention, goddess of perfume, paper, writing, healing, divination and beauty. That is frackin' cool.
Then there's Heimarmene and Pepromene, the obscure fate goddesses. Heimarmene basically the goddess of cause and effect, while Pepromene was the goddess of finite nature. They were even discussed by sects of philosophers who otherwise didn't believe in gods.
I'd have to say those two (Heimarmene, and Pepromene) and Tyche run an even tie.
“…Judge not what a man has done, but judge what he could have done if he was a different bloke altogether. For art thou a leper? And a leper can changeth his spots…” --Rudy Wade, Misfits (Series 4, Episode 8)