I needed an odd size photo sleeve to use for hand made greeting cards, and could not use the standard 4 x 6, so I was lucky, when searching the internet to find these 6x6 photo sleeves which are larger than the cards, so they fit perfectly!
I have purchased a few 3 ring 12x12 scrapbooks. I use these photo protectors to sort my stickers and embellishments. I have albums for animal, baby, alpha, travel etc. It is so easy now to see what I have and to find what I want.