One of my jobs was in a special effects shop and there were lots of scraps of wood that were being discarded. So I snagged a couple with the hopes of figuring out a project for them after the fact. One of those blocks became this handy key holder. I used:
leftover keys from offices of the past
a small block of wood
2 vice grips
I took the block of wood and sanded down edges with medium grit sandpaper. Then I antiqued it, ie: hitting the wood with a hammer. Then I stained it and got ready to work on the keys.
The keys were by far the trickiest part because they really aren’t meant to be bent. I broke two in the process, so I would have extras. I used a vice grip to hold one end of the key and then another smaller vice grip to slowly bend the keys into hook shapes. I imagine if someone were to heat up the keys they might have some better luck.
Once I got the keys bent, then I only had to screw them into the wood. To hang it I used the hardware I had in my house. I inserted the eyelets on top and then ran fishing line through them. The whole project took about an hour or so.