Lots of open pollinated sweet corn. Golden Bantam is best of the bunch, But Stowell's Evergreen, County Gentleman (shoepeg), Howling Mob, Black Mexican are still commercially available. None are comparable to modern hybrids in production or taste, but they are still grown.

Hey Tim; There are so many varieties that you can choose from.
1.Luther Hill-85 days, white kernals,extra sweet, parent of Silver Queen.
2.Texas Honey June-93 days,white kernals, produces 2-3 ears per stalk. Husks are really tight which makes them almost totally earworm resistant.
3.Country Gentleman-78-100 days,white kernals,random spaced not in rows. Great taste but not extra sweet.
There are of course a couple dozen other varieties that you could choose as well but these are easy to find.
And with "Timed Isolation" you could grow two or three varieties in a sigle season and still produce pure seed from all of them.
Example: Plant the Luther Hill, wait a week, plant the Texas Honey June, wait another week and plant the Country Gentleman.
I was also going to suggest ?
"Six-Shooter" which produces 6 ears per stalk, providing you plant on 18 inch centers. However this variety is becoming quite hard to find.