At the moment I'm using sheets of print-outs of recipes, some in protective sleeves, some not, none in any particular order, since they are printed with several different recipes on each sheet. Plus, like you, I mostly cook from memory, inspiration, or just plain "OK, what have I got on hand that sounds good"! At the moment I'm just using the recipes for things that have had to go GF, like breads, cookies, etc.
I keep saying, I've got to get organized! So I'll watch this thread with care to see what great ideas the others come up with. Thanks!