Elaeocarpus, a tropical edible and ornamental genus, has it's own selection of oil-rich fruits, with one fruit being the Himalayan olive (elaeocarpus lanceifolius). Looking like an apple-sized green olive (tasting like one as well), and having a texture reminiscent to an avocado, these can be dried, pickled, and eaten fresh. I recently planted two pits, which look like three-lobed walnut.