I have seen this is a lot of conferencing apps, but I have a lot of players that aren't good at interrupting AND DMs that don't always remember when people are waiting to chime in. It would be awesome to have some sort of indicator that a player can turn on showing that they have their "hand raised" and is looking for the DM to notice them. I think that live games bank on body language for this but roll20 doesn't offer an option.