This project was created as a black box, from scratch reimplementation of Liru/tumblr-downloader, recreating and improving upon its features.
Features
Downloads all photos and videos of a blog, including those inlined into posts
Automatically stops scraping a blog where it left off the last time
Allows filtering out reblogs
Uses Tumblr's v2 API, which is more robust and significantly faster
Simulates Tumblr's private API to even scrape private blogs if needed
All downloads are parallelized
TODOs
Documentation (up until now this strictly has been a private project)
Crawling of >5000 posts per day will lead to rate limiting
Continuing a previously failed crawl/scrape is not supported
Setting the before field in the config allows you to scrape backwards starting at a date in the past.
That way you can manually, iteratively scrape a huge blog in "sane" chunks (e.g. first everything before 2014, then 2015, 2016, ...).