CI jobs not picked up by a runner

I’m trying to set up a new runner to replace an old one. The one works fine, and at the moment they are both active on our GitLab instance. Last time I tried pausing the old runner, some users complained that their jobs weren’t picked up. I think I’ve found and fixed the error that caused that, so I would like to try again. But while it’s easy to see which jobs a particular runner has taken, I haven’t found a way to see if there are any jobs that are not being picked up, is there such a list that I just haven’t found?