Hello and welcome to the 'Shack.
I think a good place to look would be www.partsexpress.com
. They have tones of drivers.
You would first want to determine what yu need though. What kind o speakers are they? How many drivers per cabinet? Do you know the crossover specs? Cabinet volume? These are important to choosing the right drivers. Intended use playe a big roll, too. What are you going to use them for?