i wanted to clean up the list of styles in Darktable to only include those i actually use and found no way to remove them all in one go, so i looked around and found a solution.
Make a backup first in case something gets foobar!
- Located your data.db (~/.config/darktable in Linux)
- Open the data.db in a sqlite browser (sqlite in linux)
- Open table “styles”
- Remove any styles you are longer interested in by simply deleting the row in the table