The following 8 special pages appear to be missing help links, and are listed with a suggested target. This is not an exhaustive list. I'll leave this for a few days for any feedback about the targets before uploading a patch.
- Special:Blocklist -> Help:Blocking_users (https://www.mediawiki.org/wiki/Help:Blocking_users)
- Special:ListFiles, Special:ListDuplicatedFiles, Special:MIMEsearch -> Help:Managing files (https://www.mediawiki.org/wiki/Help:Managing_files)
- Special:BotPasswords -> Manual:Bot passwords (https://www.mediawiki.org/wiki/Manual:Bot_passwords) (no dedicated help page exists)
- Speciali:Categories, Special:TrackingCategories -> Help:Categories (https://www.mediawiki.org/wiki/Help:Categories)
- Special:UnwatchedPages -> Help:Watchlist (https://www.mediawiki.org/wiki/Help:Watchlist)