One Piece Chapter 511

[Splash!]

Metal. We need to have someone who can turn into metal. I mean come on who doesn't want a person to be like T-1000 from terminator 2? Everyone wants to see that.

Wood. This is kind of stupid, but I can see it being possible. Doesn't seem very strong though.

Diamond. Damn near just mean I know, but that'd be just bad ass. Good luck beating this guy.

Metal, wood and diamond could just as easily be paramecia abilities as well. It all depends on how Oda decides to use them. A DF user that can convert both himself and his surroundings to metal (using it like Aokiji does ice) would be a logia user. However, someone who just hardens their body into a metal would be a paramecia, much like Luffy.

Edit to below: So Mr. 1 had the steel fruit. I thought it was just a sword sword fruit. You never know with the parameicia abilities. They can range from very specific objects to general materials like rubber. That probably means we won't be seeing a metal fruit.