Someone with the handle "user0068" on GameFaqs has done some amazing work documenting item drops, enemy spawns, cune locations, and more.

The document is available here: https://docs.google.com/document/d/1G9Wu-NHmm0wnMqiypGtXSHzcgbLy_tg4s9yJc7qhtH8/edit

Here's the thread they created chronicling their process: https://www.gamefaqs.com/boards/198605-shadow-tower/72854675

Let me know if the Google Docs link becomes broken, I should have a backup if needed.