I made a new LaTeX package called
bibcop (it's already in CTAN): a style checker for BibTeX bibliography files (.bib). You just add it to your document and it emits warnings into the TeX log when/if style problems are found in the .bib file. Moreover, besides checking the files bibcop can auto-fix them. It is also shipped as a command line tool:
$ tlmgr install bibcop
$ bibcop --fix main.bib > fixed.bib
It is pretty strict already, but if you think it's possible to make it even stricter, please submit an issue to GitHub (also, if any bugs found).
