My recent mail order purchase of vegetable seeds from Peaceful Valley heightened my awareness of seed suppliers.
Recently I again visited Wildscaping.com and re-discovered their short list of seed suppliers. Of course they have an emphasis on California natives. Here's a link to Wildscaping's seed supplier list.
Among certain types, garden machismo accumulates with the number of plants that you raise from seed. I don't think that I'm buying into that belief, but I am discovering the convenience, economy, and selection available in seeds.