These are simple tools that I carry in my wallet to extract credit cards or my drivers license from tight wallet sleeves. To use them, slip the tool beneath the stuck card with the protrusion facing up. Work the protrusion under the bottom end of the stuck credit card, then pull it to freedom.
I am posting all three variations of the design, although I find version 3 the easiest to use. Having given a number of these away to people who have seen them in action over the past year or so, I am posting them for anyone else who struggles at times to remove a stuck credit card or ID card.