My character is a cannibal, and he collects body parts of those he kills. I've been looking for some chart, or something that has the weight of the individual parts of the various sized creatures to give to my DM and know how to fill out my inventory. The system I am using is pathfinder.
All the races have weight ranges, in addition to age and height (Dwarf, Elf etc.). Work out how tall the body in question is, or take the average weight if you don't know the height, then divide the weight up: This Kinesiology webpage provides percentages for humans, so it might need fudging for other races, but it provides some starting numbers to work with.
This forum question also provides percentages for body parts, but highlights that they can change over time, so the percentages aren't absolute; you may want to research more statistics and aggregate them for a more average set of data.
In case the above links disappear, some average-ish percentages, Plagenhoef et al., 1983:
I appreciate you might be looking for a more pathfinder-oriented chart for these statistics, but your question appears to cover quite a specific (and personally never before considered or seen) circumstance, and I think that there simply isn't that kind of consideration in any existing publication.
I'd really talk this over with your DM, in all honesty.