Additions
- [furaffinity] extract more metadata
- [instagram] add `post_shortcode` metadata field ([525](https://github.com/mikf/gallery-dl/issues/525))
- [kabeuchi] add extractor ([561](https://github.com/mikf/gallery-dl/issues/561))
- [newgrounds] add extractor for favorited posts ([394](https://github.com/mikf/gallery-dl/issues/394))
- [pixiv] implement `avatar` option ([595](https://github.com/mikf/gallery-dl/issues/595), [#623](https://github.com/mikf/gallery-dl/issues/623))
- [twitter] add extractor for bookmarked Tweets ([625](https://github.com/mikf/gallery-dl/issues/625))
Fixes
- [bcy] reduce number of HTTP requests during data extraction
- [e621] update to new interface ([635](https://github.com/mikf/gallery-dl/issues/635))
- [exhentai] handle incomplete MIME types ([632](https://github.com/mikf/gallery-dl/issues/632))
- [hitomi] improve metadata extraction
- [mangoxo] fix login
- [newgrounds] improve error handling when extracting post data