Sarasota High (FL) has produced 51 professional players, according to thebaseballcube.com
Destrehan
Corsicana High School
Woodland Hills High School- Pittsburgh,PA
Griffin
Glades central high
DC Everest
Oak Hill Academy
William m raines jacksonville, Florida
I am not sure, but I know one high school in Long Beach, Ca has produced well over fifty NFL players, and that is Long Beach Poly High School. This would be a good place to start your answer.
As for High Schools Oak Hill Academy and Dematha have produced many, and as for University, UCLA, North Carolina and Duke have produced the most.
Miami has produced 55 pro players. That is the most from a school. hope this helps