I think breed has less to do with, then quality of past training, experience and overall temperament. Having said that, there are breeds that tend to be more agreeable in general.
Quarter Horses are a nice choice. Some smaller draft crosses can be quite nice...sturdy and laidback. Appaloosas are usually suitable. Paints not so much...tend to be a bit too strong minded, but a Paint cross might work nicely. Standardbreds are idiot proof, but can be frustrating to retrain as suitable mounts...so if you go that way, you need to get one that doesn't have canter issues. There are lots of pony breed choices...that's a very one on one issue as a lot of ponies can be just brutal.
Again though, suggest that age, training and temperament be your first criteria.