A "good" pedigree is a matter of opinion - a dog that has an outstanding pedigree for mating to one bitch may be a complete disaster for another. It would probably be better to state what lines you are looking for to best compliment your girls pedigree.
A good place to look for working labs at stud is on Ukgundogs (www.ukgundogs.org). Most stud pages will give you pedigree and health results (hips and eye status) Eavie