Jot
Back in my Corporate Clone days, I started with an index card case. Soon I upgraded to a pocket briefcase from Levenger. It doubled as my everyday wallet.
I've switched to a RFID blocking wallet that keeps my cards from being scanned. And I've switched back to a separate index card case.
Now to make this work, you can't use standard index cards, they are oriented the wrong way. Levenger makes some premium cards, but you don't need those. I prefer a grid card over ruled.