Many moons ago, there was a berry farm in Wisconsin that had piles of surplus WWI and WWII Haversacks. They cut off the flaps and straps and used them as picking bags...
These are some of the lower straps that were removed. The pieces are generally 12"-18" or so long and some have slides and snap hooks. Condition varies from mint to worn, most of the hardware has at least some corrosion. How many? About like in the photo- we fill gallon zip-locs full.