We have 492 deleted questions tagged untagged. Yes, deleted questions have tags too! They just don't count for the number of questions tagged as such.
Moderators can search for and edit deleted questions and this doesn't trash the homepage, so I started doing just that. Most of those are "identify-this-game" or "game-rec" anyway. There is one side effect however: every time I apply a tag to a deleted question, the tag counters are updated as if it was a regular question. As a result now /tags says there's a bunch of questions tagged "identify-this-game" when they're really only two questions (both awaiting certain deletion.)
I suppose tag counts are updated hourly/daily/weekly/full moonly/manually/every Saturday in Iceland, so eventually this will fix itself. This is still a (really really minor, really really petty, "why the hell are you doing this in the first place?!") problem.