Google says that some of these are alternate name and more easily found under their more common names.
2. Early York cabbage = Early Jersey Wakefield cabbage
3. New Giant asparagus = Jersey Giant asparagus
4. Large White Flat Norfolk turnip = Early White Flat Dutch turnip
7. Round Leaf Spinach = probably Malabar Big (Green) Round Leaf, but Giant Noble also has large round leaves, there's also a Chinese Spinach with round leaves
9. Long Dutch parsnip = Half Long Guernsey/ Half Long White
14. Celtic fava bean = Horse Bean/English Bean/Broad Windsor Fava
For the above I recommend checking with Baker Creek to start with. They popped up a few times in my searches, and probably have some of these if not all of them.
Old White eggplant did not bring up a specific variety with a more commonly known name.
I could only find a vintage seed packet for the Large Late Drumhead Cabbage. Lone Star Seed company of San Antonio, Texas sold it for 10 cents. Mary's Heirloom Seeds has an heirloom drumhead cabbage that can get up to 10-12 pounds. It looks similar to the illustration from that vintage packet, at least it looks similar to me.
https://www.marysheirloomseeds.com/products/drumhead-cabbage
For the Spanish Red sweet potatoes, they could also be the Boniato and I found a source on Etsy for those.
https://www.etsy.com/listing/4316748440/boniato-sweet-potato-tops-organic-ready?ls=s&ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=boniato+sweet+potato+slips&ref=sr_gallery-1-4&sr_prefetch=1&pf_from=search&sts=1&content_source=1e0f83c2-e73f-4491-8af6-9dcaa02d8742%253ALT0f6adf189b0e95be7b1db3847417bf7937af0a4f&organic_search_click=1&logging_key=1e0f83c2-e73f-4491-8af6-9dcaa02d8742%3ALT0f6adf189b0e95be7b1db3847417bf7937af0a4f
I could only find Red Valentine beans in a bush variety.
Yellow Guinea Flint Corn seed can be purchased from the Montecello shop.
https://monticelloshop.org/products/yellow-guinea-flint-corn-seeds-zea-mays-indurata-cv?srsltid=AfmBOoroAYYpaY_DaWqx0KW_M0hvzFle63VdSji-lsabh_i3dTtsXvWz
Sand Hill Preservation Center might have the Disc Nantes gourds for 2026. They haven't updated their Gourds page yet.
No luck on the Yellow Sioux flint corn or the Crown Imperial pea. I did find a great reference website for food in the colonial period of the USA's history that mentions Crown Imperial as the best pea in terms of flavor.
Good luck with your search. I hope this help some.