If you want a simple minimalist wallet with lots of card slots to organize your cards while keeping the wallet as slim as possible, you might want to take a look at the Wallace Minimalist Wallet. This slim wallet that is currently seeking funding on Kickstarter is as simple as it can get but it somehow managed to squeeze in a total of 6 card slots plus a fairly large center cash slot for carrying all your cash plus other knick knacks like receipts and paper notes.
Many slim wallet designs sacrifices organizational space for reduction in bulk by forcing users to store everything in just one or two separate compartments. This makes the wallet very space efficient but unless you are a very well organized person who always store your wallet contents in a very specific manner, it also makes searching for that one card a little more of a hassle. The 6 card slots provided by the Wallace Minimalist Wallet makes organizing your wallet and extracting the card you are looking for much easier. The staggered layout of the card slots also makes it easy to identify your cards with just a quick glance.
The Wallace Minimalist Wallet measures just about 3 inches (7.5 cm) by 4.1 inches (10.5 cm). Besides the card slot there is also a cash slot that fits most if not all currencies. There is just enough elasticity in the wallet material to hold everything securely but yet not make it too difficult to slide cards and cash out of the slots. The wallet is made from synthetic leather and is 100% vegan.
As of time of writing, the Wallace Minimalist Wallet is about halfway to meeting its funding goal on Kickstarter. With just a minimum pledge of just $10, you can be one of the first in the world to receive a Wallace Minimalist Wallet.