Pixiv User Filter od Shajirr

This addon allows you to exclude artworks of specific users from showing up in Recommendations section as well as tag pages by adding said users to a blacklist.
Their artworks will be simply hidden. The addon will display a counter to show how many artworks it removed.

It also has an optional function of excluding the artworks of the author on who's page you are currently on from the Recommendations too.

Usage instructions:

• To add a user to a blacklist, right click a link to a user's profile,
  which would be in a format like "www.pixiv.net/en/users/<user_ID>",
  go to "Pixiv User Filter" -> "Add User to Blacklist". Removing a user from blacklist
  can be done in a similar way, just choose the option "Remove User from Blacklist" instead.
• Another way to add/remove users to a blacklist is to edit it directly in the addon's
  Options page, by manually adding/removing the user ID(s). The format of the list
  is each user ID on a new line. Click Save button to save the changes.
• You can see how many artworks were removed either above the artwork grid to the right
  of the grid header, or on the addon icon on the toolbar, assuming the addon icon is pinned.
• If you also want to remove the artworks of the user who's artwork you are viewing
  currently from its Recommendations section, check the appropriate checkbox
  in addon's Options page.