Socks!

When my kids were little we seemed to have socks everywhere!

When they were still wearing socks with cuffs (that roll down at the ankle) we would mark each sock with a line about 1/4" long using a Sharpie marker. 1 mark meant it belonged to the oldest kid, 2 marks, 2nd oldest and as the kids handed down the socks we just added a line to show who it belonged to now. Every now and then we'd go over fading marks. But this really made sock sorting go MUCH easier.

Anything from the dryer without a match went in to the Sock Bucket (a wash tub or whatever container we were using at the time). Occasionally we would need a "time out" activity and someone would sort for a certain amount of time or until they had a specified number of matches.  If the bucket started to get full and nobody had been on sock matching duty, we'd dump them in the middle of the floor and have races to see who could get the most matches in 5 minutes.

Again, when the kids were little and I was more concerned about their socks matching their outfit, I even put baskets into their closet and sorted the clean socks by color. Labeling the buckets gave the pre-readers some practice at seeing the color written in context with that color socks inside the basket.