I have a wallet for all daily use cards + membership cards, but use this for storage of all cards I have + retired cards in back.
I use this for my currently active cards: https://www.amazon.com/gp/product/B001PMG7UE It's nice and sturdy and each of the slots could hold 2 cards if you want to keep your AU cards or World/World Elite upgrades together.
Anything that I close or receive a replacement card I usually destroy the old card.
I've got this for storage: Amazon Link
Then my every day wallet with 3-4 cards at a time.
And finally my "MS" wallet which is one of those flat non folding wallet that has all "to be unloaded" GCs, Buxx, and Serve cards (I don't MS heavily so never more than 3-5 GCs at a time). I throw that in my pocket/car when I know I'll have a chance to do some unloading.