I was looking at some old Irreal posts and stumbled across this post. It’s something that I’d completely forgotten about so I thought it would be worthwhile pointing to it again.
The TL;DR is that when using Magnar Sveen’s excellent Multiple Cursors you can narrow to the matched lines (and a little context) by calling
mc-hide-unmatched-lines-mode. It’s really handy when the targets are spread out in a larger buffer because you can see all (or at least more) of the targets on the screen. Take a look at the original post for the details.