Nearly all warmbloods are bred to be exceptional at jumping/dressage (pretty much the point of warmbloods). Most thoroughbreds are also quite good at it too. However, the most important things will be conformation and temperament.
One of my favorite articles about jumper conformation: http://www.jwequine.com/pdf/conformation101-jumper.pdf
It's probably most important to find a horse that LIKES
jumping, and is SOUND
enough to handle the workload =D.
Hope that helped!