Oh, this is just too amazing. I have laminate floors and have gone almost crazy trying to keep something on the bottoms of chair legs to prevent scratching. I do a lot of stuff with dogs and I already knew there are smaller tennis balls for small dogs so when I started googling I found pre-cut tennis balls for chairs. There were a couple of different sites. One has a lot of different colors and another had different sizes. So if you are looking for something in, say, your kitchen or living room it might be possible to get something that blends in a bit better than a the standard bright green tennis ball.
Wow! Pre-cut tennis balls? Who knew? Personally, for my sewing stool, I like the look of the bright yellow. I always try to stay a little eccentric -- it throws people off a little!