You might think about this from the 'other direction'? What patterns do you use most frequently for scraps?
I have a couple of go to patterns for quick scrap quilts and cut left-overs accordingly. The first option is a 6.5" square that can be used uncut with 9 patches of 2.5" squares or a square within a square made with 2.5" strips.
Rather than cutting into squares, I generally save strips of various widths. 2.5" goes in a box with left over binding and can be cut later into squares, bricks or strips for log cabins, scrappy binding etc.
5" charms are always useful. 3.5" squares go with four patches of 2" squares but I have stopped keeping these.
I keep 1.5" and 1" strips for string blocks.
Not wanting to waste any scrap of fabric, I used to cut into more sizes, but found it over complicated things and I had fewer of any size when I came to using them. The important thing is to use scraps rather than collect them. A lesson that took me a while to learn!!
