I used to be vegan and I would indeed eat a lot of quinoa and lentils. I also ate a bit of buckwheat, sweet potato, brown rice, and organic baby kale IIRC. Less frequently I would also eat:
-black and red lentils
-other grains like amaranth
-tofu and tempeh
-Ezekiel bread(IIRC they have a salt free bread)
-Garden of Eden beans(though I would sometimes cook my own beans)
-black rice
-purple sweet potato
-purple potatoes
-blood oranges(my favorite oranges)
-flaxseeds
-cherries and berries sometimes (can't believe how cheap frozen cherries were at Grocery Outlet. I think they were even organic IIRC. I don't go shopping anymore though)
-papaya, pineapple, mangos, bananas, dried dates, dried mulberries
I've tried unusual foods like jackfruit, cherimoya, uncommon mushrooms, dandelion, and fruits I don't even remember the name of. Sure, they might not seem that uncommon, but these aren't really available at Kroger. I'd often choose organic but not always.