Here is a simple design for a back-leaning business card holder you can make yourself. In case you want to know how far back the card holder is angled and other measurements, see the diagram showing a side view of the holder before and after it's rotated. If there is a dimension you want to know but don't see, have a go at filling in the blanks yourself. For a general rule of thumb, make the inside of the business card holder 2mm wider than the card width on each side and extend the top of the backing plane 3mm taller than the height of the card from the top of the cardholder's base.