I stumbled upon this when I started brewing,
Brewers grains | Feedipedia so with it in mind I try and utilize as much of the spent grains as possible whenever something is being baked. Thus far, we've added either dried or dried then pulverized to:
Pizza Crust
Sandwich Breads
Various other breads (Zucchini, Pumpkin, Banana)
Muffins
Pancakes
Pooch will get the occasional spent grain dog biscuit, but for fear of him being referred to as "Ottoman shaped" by our vet again, it doesn't happen very often.
I eat steel cut oatmeal every morning and add flax. Think I might try and add some of the ground up spent grains tomorrow morning and see how that turns out.
Whenever we don't have room for more grains, they get put into various vermicomposters I have on our side yard.