Concrete information about Wolverine 3 (not final title) is hard to come by. We know it's starring Hugh Jackman, playing the role for "one last time" as he has teased. We know it is at least somewhat based on the comicbook storyline "Old Man Logan," featuring a Wolverine in the future attempting to live a somewhat normal life in a world ruled by supervillains, and that it's shooting for an R rating. We know a couple of other stars, like Boyd Holbrook, Stephen Merchant, Richard E. Grant, and Eriq Lasalle, though we have no idea who any of them are playing.
Now, Nerdist reports that a source says the villains - or at least the canon fodder villains - of the film will be the Reavers, cyborgs created specifically for the elimination of mutants. They still don't know who is creating the Reavers, or controlling them, or to what capacity the characters are being used, though speculation includes Donald Pierce and Mr. Sinister as top suspects.
Several popular Wolverine stories have had him running a gauntlet of villains, of course, so the idea of there being more than one - even drastically more than one - villain is a pretty high chance.
The movie, directed by James Mangold and starring Hugh Jackman, is shooting in New Orleans now for a March 3, 2017 release. Wolverine can next be seen in a cameo role in X-Men: Apocalypse on May 27, 2016.