Pads are another important concern for your horse's back. The traditional Western blanket doesn't work very well. It has little resiliency and covers too large an area. As to material, natural wool pads with a foam lining often work the best. If you can't afford wool, Kodel is the next choice.
Some saddles have a custom made pad built in to achieve the same result.
Too many pads or pads which are too thick allow the saddle to roll. A stack of pads can also cause the back to retain a lot of heat. Whatever type pad you use, the shape of the pad should match that of the saddle. Especially in hot weather, you don't want to cover any more of the horse's back than necessary. Breast collars, cruppers, and bridles come in nylon, leather, and Bioplastics.