On the search page, you can bookmark all works on this page (Patreon)

This feature has been added in version 6.4.0.

https://github.com/xuejianxianzun/PixivBatchDownloader/releases

Open the download panel on the search page, there is a button "Favorite all works on this page" in the "Other" tab, click it will automatically grab all works on the current page, automatically collect, automatically add tags.