This project was made easier by the efforts of many other community members who published their data publicly, and by other third-party developers who made the tools that made this project possible.
Leather Shipment Drop Rates
Thanks to the following Wiki users, YouTubers, and Redditors for contributing their research to the community:
Karob; peetftw.7286; Kalix.1406; Hal42; Yoruu; Kulgin; MaxOS1104
Trophy Shipment Drop Rates
Thanks to the following Wiki users, YouTubers, and Redditors for contributing their research to the community:
Monoreign; KasparMk5; Aikala; Trutichup; Khisanth
Salvage Rate Research
Thanks to Mystic.5934 (Toothless Biter) (/u/colbymg) for compiling and publishing a great set of salvaging data for the community!
Thanks to ArenaNet for creating the official GW2 API which was used for live pricing data, and which prompted me to briefly consider using full listings too.
Thanks to GW2Spidy / its creator Drakie for making a phenomenal trading post site, and a hugely valuable API for trended pricing data!
Thanks to GitHub user bradjasper, along with Trevor Lohrbeer, Karsten Lettow, pbazerque, Rafal (kenorb), and Luis Lobo Borobia, for creating a wonderful custom Google Sheets function allowing for the direct import of JSON API data to a spreadsheet. Without that function, this wouldn't be possible!