Throughout 20+ years of DMing and three editions of the game, I've had players who wanted to make trophies, potions, and magic items from the carcasses of supernatural creatures they've vanquished, and I've always had to BS my way through it. Hamund's Harvesting Handbook is a comprehensive system that satisfies your waste-not-want-not, Witcher-emulating players. It has the following:
- A system for assessing & harvesting creatures, with different skills required for different creature types & rules for decomposition of corpses
- Extensive tables for every creature in the Monster Manual, specifying exactly what can be harvested from each creature, the GP weight and DC for said harvestables, and what they can be crated into. It also accounts for things like "Devils don't leave behind corpses" and "elementals don't really have bodies,"
- A bunch of new items all ready to be made from bits and pieces of monsters, all well balanced, with actual crafting rules for making them (beyond Xanathar's Guide's rules).
With a little study this sytem will fit right in to your campaign. Bear in mind that this will let your characters get a little more gold value from their kills by harvesting valuable components, but the gold values aren't excessive and when they're measurable, it's for creatures like dragons, who should be worthy prizes.
Definitely recommended, I can't wait to pick up the other books in this series.
[5 of 5 Stars!]