NeoDownloader - As you know, there is a lot of websites with a lot of pictures, music and movies.
Boorusphere - Yet another booru viewer for Android.
WFDownloader App - A free bulk image downloader application that also serves as a multi-purpose bulk downloader for your PC.
Booru Nav - an app designed for simple browsing at different anime imageboards.
Transloader - Start downloads on your Macs, remotely from other devices
LoliSnatcher - A booru client with support for batch downloading, written in Dart/Flutter for Android but may support more platforms in the future.