I’d mentioned that my Steelcase card index came without the traditional card stops/follower blocks at the back of the drawers. Needing a solution for this, I’ve discovered that my local Daiso sells small, simple bookends for $1.75 for a pair and they’re the perfect size (7 x 8.9 x 9.2 cm) for the drawers. These seem to do the trick nicely, though they do tend to slide within the metal drawers without any friction. Giving them small rubber feet or museum putty from the hardware store for a few cents more fixes this quickly.