Like the OP, it’s the oddball varieties I can’t find in the store that I like to focus on in our garden.
Some eccentric favorites that offer good taste, yield, and pest resilience are:
Creasy greens / upland cress
Erbette chard
Collards (I’m a Southern boy)
Sunchokes (best to do these in a wine barrel cut
In half and filled with compost)
Okra (when I’m living in hot humid climates)
Hakurei turnips (these are lights out delicious)
Jealous. We moved to a small house this year and have shut gardening down for a minute.