Mine I use spinach, ginger, frozen strawberries, (i get them free during the season and freeze a bunch of them, same with blueberries) banana, kiwi, muscadine grapes, which I get free and freeze as well. Nice to live near farms and get free stuff.
Also done, yellow squash fresh and frozen, cucumbers, chia, milled flax seed, lemons and even gone as far as when we cut up a watermelon, I clean the rind and cut it up and freeze it to use.
Broccoli works well but be careful it can make it taste off if you put to much in. Also Tart Cherry concentrate. Good for inflammation.
We have a Vitamix so not much doesn't get put in. Peanuts are good but not much, they give a strong taste. Almonds and cashews as well. We buy a lot of bulk at Sam's Club and Costco.