There are 2 repositories under doujins topic.
Enma is a Python library designed to fetch and download manga and doujinshi data from many sources including Manganato and NHentai.
Telegram bot for nhentai
Scrapes nhentai for doujins when given various queries
A searchable database of Touhou doujinshi translations
Quickly get to your favorite doujins on nHentai
a debian optimized downloader for them doujins
Extensión para Chrome y Edge que nos permite descargar doujins desde nhentai en pdf.