When asked what Devil Fruit he'd like, Oda names two, both of which lack power but are incredibly useful in other ways. Firstly, Oda states that he wants the power of the Suke Suke no Mi.

Though Sanji has remained uninterested in devil fruit powers for the most part of One Piece, Chapter 464 revealed the one exception to this rule, which was Sanji’s dream to eat the Clear Clear ...