Franky is one. But to be fair I think everyone in the straw-hats are unlikable except Zoro, but Franky especially. The franky character is specially bland and dead without a spec of anything interesting about him or anything going for him; I don't think anyone bothered to mention him here because he has Zero presence no one even remembers him.
The stuffed toy, chopper, is the next most unlikable character. Then, Nami, Ussop, Sanji, Goofy, and Niico Robin. I actually like the skeleton and the fishmen.