I mostly work in a scrappy style with the design concept of color or value -- so instead of 1 blue, I'll use 6 or 60... What I've found over the years though is I don't like dealing with little bits of fabric and that if I cut all my little bits into little squares, I would never ever be able to finish up my little bits to make quilts I wanted to make. Some people, on the other hand, love the idea of having tons of available 2.5" strips and squares or whatever size they determine. So often what we make is determined by what sort of scraps do we have. I've ended up that I don't keep anything smaller than a 6.5" x larger than a square because "I can always cut down but I can't cut up". I have a box at my cutting table and a lovely crumb quilter from the board takes my boxes of weird stuff as I fill them up
Bonnie Hunter is considered a queen of scrap quilting. You might browse/spend hours at her site!
https://quiltville.blogspot.com/
A lot of what I do is really more about collections of fabric that have some sort of theme or reason why they are a collection, than really about scraps. Both of these quilts came largely from the same box of various sized pre-cut squares I was given but I did add some fabrics. First, I took out all the squares that had metallic embellishments and made "scrap metal" by cutting the squares into consistent sized triangles and sewing them back together with a sashing fabric out of stash. In the other, I took out all the large bright novelty prints and cut them into a consistent size. I framed them with a consistent confetti fabric, and then I took the remaining bright squares into rectangles for the sashing.