Seeds - Organic Databases
Carolina Farm Stewardship Association offers resources through their search engine, including reports about a number of regional organic seed sources. Enter "organic seeds" in the search bar.
Saving Our Seed Project - The Carolina Farm Stewardship Association was previously linked with this organization, that offers comprehensive information about saving seed and preserving the quality of the seed through handling practices. They appear to no longer source seeds.
Washington State University
Vegetable Research and Extension program
The WSU Vegetable Research and Extension program, based in Mount Vernon, Washington, "includes a wide range of projects such as screening new crops and breeding lines for suitability for production in Western Washington, testing new products such as degradable mulch and high tunnels, evaluating integrated pest management strategies, and implementing water and soil conservation practices.
In January of 2006 the WSU Center for Sustaining Agriculture and Natural Resources produced a list of organic seeds by variety and that is now only available through an Internet Archive page:
https://web.archive.org/web/20070203110852/http://csanr.wsu.edu/Organic/OrganicSeed.htm. That page has a "click here" link to a 554-page PDF file (test download was successful) of a long type-written document about seeds and sources.
Organic Seeds Partnership
The Cornell University Organic Seed Partnership, sponsored by the National Institute of Food and Agriculture, will enhance and expand a set of existing complementary, regionally-focused activities to create a strong national network aimed at developing and delivering improved vegetable varieties selected for superior performance in organic systems.
Organic Seed Alliance
The Organic Seed Alliance has created a Seed Producers Database. The Seed Producers Database is designed to facilitate connections between seed growers and larger-scale seed purchasers. Both seed growers & seed purchasers can reach a wider audience more easily through the OSA Seed Producers Database.
ATTRA - National Sustainable Agriculture Information Service
ATTRA used to run a database for suppliers of seeds. This 2006 list is only available via the Internet Archive at: https://web.archive.org/web/20060206090459/http://attra.ncat.org/attra-pub/altseed_search.php You can search on the sites listed to see if they're still operating as they did in 2006. Some national, mail-order suppliers of untreated seed were included, with the emphasis on small alternative seed companies offering open-pollinated vegetable, flower, and herb seed.
Though the list is possibly obsolete, the ATTRA website is searchable and has a lot of sustainable and organic information, especially if you search it's newsletter archive.
Updated January 2021