Automatically adds artwork tags when you bookmark. ブックマークのタグを自動的につける。
< Opiniones de Pixiv Ajax Bookmark Mod
It doesn't work there because you can't see the tags on that page. You will have to open each image one by one if you want to add it with tags.
Does this work with https://www.pixiv.net/showcase/ ? (regarding the auto-tag adding)
It didn't seem to work for me with the showcase, maybe I was just not capable.