Illustail is described as 'Image browser for Tinami, Danbooru, Tumblr, Mastodon, Misskey, Pleroma, Bluesky, Dropbox, and photo album' and is a Mastodon Client in the social & communications category. There are more than 10 alternatives to Illustail for a variety of platforms, including Android, Windows, Android Tablet, Linux and F-Droid apps. The best Illustail alternative is Gallery-DL, which is both free and Open Source. Other great apps like Illustail are Hitomi Downloader, Aria, Boorusphere and Imgbrd-Grabber.
gallery-dl is a command-line program to download image galleries and collections from several image hosting sites (see https://github.com/mikf/gallery-dl/blob/master/docs/supportedsites.md for full list).
Boorusphere is an open source booru client written in Flutter. It supports a.o. searching, playing videos, has a theme switcher and a drawer menu, and much more.
Very customizable imageboard/booru browser and mass downloader, with powerful filenaming features.
Dhaaga is a third-party app with a focus on browsing, general SNS features and chat based use cases.
A booru client with support for batch downloading, written in Dart/Flutter for Android but may support more platforms in the future.
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