I like going for blackberries for the fruit and for growing in the muddiest places. Ssly the more you go ankle deep in mud the more you find them. Once I made almost 2 kg in 2-3 hours.
Jane and I always collect wild mushrooms and blackberries from the railway sidings along with having tomatoes and a pear tree in the garden. We have never thought of it as foraging.
Mesquite pods, cactus fruit of all sorts, dwarf mallow when the dog doesn't beat me to it, Been wanting to look into edible freshwater macroalgaes more but think I'd only be harvesting clonal mass like I did with the hornwort from lake Arivaca which seems to have doubled in size in 11 days. Testing it's potential as a fertilizer post-anaerobic digestion stage, giving it 3 weeks to turn to sludge in a bucket before blending with the compost for making aerobic tea.