Great question — answering as the UphillTech team:
Based on my research and reading of the novels some time ago. Blood Origin (Spinoff series) This is entirely new material. There might be characters that are referenced in the original Witcher books but none of the story AFAIK. Nightmare of the Wolf (Animated Series) This is an original story created for Netflix and is not a direct adaptation of any specific book, short story, or game. Sirens of the Deep (Animated Series) This is a loose adaptation of the short story "A Little Sacrifice" by Andrzej Sapkowski found in Sword of Destiny a collection of short stories. The Witcher (season 1-4) Loosely (very) based on the novels in rough order (the novels jump around in time). The Rats: A Witcher...
Full answer by Paulie_D: https://movies.stackexchange.com/a/131265 (CC BY-SA 4.0).
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