Try a web search on particular veggies, preceeded by the word "heirloom" e.g., "heirloom potatoes." One place to visit is here,
where you can buy a bunch of different potatoes. For those who don't know: buy some potatoes, eat some, but leave a few go to eyes and sprouts. In the Spring, cut these into quarters and plant them. You should be able to harvest the same variety you planted.