Honestly any song they've never played live will be neat to have, and I'd personally love to hear SFN at the concerts I attend
But more than anything I want more unique live arrangements. I love LOATR right now, but crave some interesting stuff like the Blackout/Papercut mashup or Wastelands/Runaway. I don't think we've really heard any major unique arrangements involving anything from OML or FZ yet for example, bring on an extended outro to Two Faced or IGYEIH that has me wanting to listen to live versions more than the studio ones
Maybe play a melody from OML over an extended outro, do a verse from MTV somewhere, etc. These bits have always been my favorite and I loved the crazy arrangements 2014-17 and want more of that, less of unaltered studio songs