I tend to go for some of the more obscure stuff simply because I'm curious and like to get stuff you can't buy in the shops!
Weird things I've tried in the past few years and didn't grow again: Yacon, Oca, Ulluco, Root Parsley (like parsnips), Potato onions, Quinoa.
Weird things I've tried and kept because they're good: Taunton Deane tree kale, Achocha, Everlasting onions (multiplying spring onion), Caucasian Spinach, Lady Godiva pumpkin (naked seeds for eating), Babington's Leek, Hooker's Chives, Chufa, Pipiche (coriander like mexican herb that bolts less)
Normal things I couldn't be without that are not on your list: Swiss Chard, all the soft fruits (blueberries, currants, raspberries etc.), rhubarb, lettuce, cucumbers, outdoor tomatoes, globe artichokes, asparagus.