Hey, I'm looking for all types of seeds that are heirloom. Is there a single company out there that specializes in these seeds?
There are a lot of them.
Here is a link that might be useful: Seed Savers Exchange
Seed Savers Exchange, certainly.
Other companies that deal exclusively with open-pollinated varieties:
Baker Creek Heirloom Seed
Sand Hill Preservation
Southern Exposure Seed Exchange
A couple more I've had good luck with......
Heirloom Acres Seeds