All types of fishing lead out there - here I find it mostly on beaches, campgrounds, potholes in rivers, mostly trout and salmon gear - once dug 18 homemade gill net sinkers, though the linen net was long gone.
You may find stuff we don't use - sinkers used in "trot lines" or other warm water gear.
Post a few, I'll give you my WAG - hope others chime in on this lead mystery. I know there's lead in batteries, but that's it.
PS - fishermen pay for lead to remelt - I sell mine on CL