I posted some BibTeX style files to GitHub. I generated these files over the years using the custom-bib LaTeX package. Where I could find my copy of the .dbj file I have included it as well. You can make modifications to the .dbj file and re-run them to create modified .bst files.
I haven’t tested these style files extensively, but they met my needs writing manuscripts for these journals. They have mostly been tested with journal articles, technical reports, and books.
So far, I have posted styles for these journals:
If I can save one person from having to answer another ~99 questions from makebst.tex, posting these will be a success.
We could use a better repository of existing .bst files.