Help With Displaying Figures

Does anyone have any advice for displaying figures when your shelf space has run out and you have a small room for all your figures? I don't have the room for the nice glass cases some people use and I've already used up all of my floor shelf space. I was thinking using wall shelves but nails and screws aren't an option either which led me to think mounting small shelves with putty might work but then I figured that might not hold up over time. I was hoping someone might have some magical solution who has run into the same problem.