From experience and in my opinion the dog breed that is most likely to bite is the Pit Bull especially if they've been trained to bite.
Then after the Pit Bull you have the Rottweiler and then the other dogs that have a habit of biting for no apparent reason are the, Pit bull mixes, German shepherds, Bullmastiffs, Wolf hybrids, Huskies and last but not least the Akita.
Although I have been around a few Pit Bulls that were very loving but they were treated with love as well and weren't raised to be mean.