A Medium Book Keeper!! This Size is great for carrying around multiple small paperbacks, fits bigger paperbacks and some hardcovers. This is a great middle-ground for casual readers. Including the same pocket on the front but slightly bigger for more highlighters, sticky notes or pens.
I don’t own this pattern but you can find it on etsy:
https://mlgsewingpatterns.etsy.com/. It was a super fun pattern to make!