I am sure this idea is not original, but it’s something that I recently started doing with Emma’s toys, and it is working WELL for us!
I don’t feel like E has a TON of toys, but she prefers smaller toys, which are messier. I’m really trying to get a hold on clutter around here, so I decided to do the box system with her playroom toys.
I bought some clear boxes w/ lids at Dollar General for $1/each, and I have different toys in each box.

I waffled about labeling them, because I’m sure the contents will change over time – plus, they’re clear, so I can see what’s inside. For now, I think I’ll just leave them label-free.
So the rule is … one box at a time. She can make a huge mess with one box, but if she wants a different box, she has to clean up the first one.

She’s not into stuffed animals, and they’re easy to pick up, so they live in the blue and green canvas boxes. The remaining cubes in the shelving unit hold puzzles (we only keep 2 at a time in her playroom), coloring books, and reading books.
She also has a set of wooden blocks and a set of foam blocks that stay in the downstairs closet, which I cleaned out and re-organized a couple of weeks ago.

I am currently in the process of cleaning out the rest of her toys. I have a few boxes packed up for future baby, but there is some that she doesn’t like that I don’t care to keep.
Side note: she’s currently walking around with one of her baby dolls, patting baby’s back, and saying, “It’s okay, baby. It’s okay.” Awww.
I am also working to get this office / playroom cleaned out so that I can paint it. And possibly get hardwood put down if we can scrape up a little extra moolah. But that’s another post for another day.
I need to go tend to these piles of paperwork, now …