Help! I need some ideas on how to display my SO's toy collectibles, which consists of action figure toys ranging from Transformers, comic book toys and video game toys.

I'm okay with showing a few here and there (I've limited him to displaying these in the game room and our office), but his collection has grown, and now I'm not sure how to display them. There isn't much of a commonality between the action figures. They're all of varying sizes, colors and shapes.

And worst yet, he insists of keeping them in their original boxes. Granted, this makes sense for keeping a collectible in good condition, but I think that's going to make it that much harder to display them well.

Right now, we have the figurines (in their boxes) stacked on top of an Ikea book shelf in the office. In the game room, we have some floating shelves where we have also stacked figurines on (see picture). I would say that both of our design styles are a bit contemporary, but we definitely do want to have a warm, cozy, and fun, yet grown up vibe for our game room and office.

Any ideas on how to display these without making the room look cluttered or too childish? Thanks!