I was looking to print a key holder to go next to my garage door in my kitchen. I don't have a lot of space there, so I wanted to get something that would look good, fit nicely, and be reliable.
After a lot of scouring the interwebs, I happened across the excellent key hook, posted by HaBen. While the original design was awesome, I saw in his images an example where the face plate was on both the top, and bottom, and that gave me an idea.

I doubled the height of the frame, and swapped out the hooks for pegs instead, lending to some stability and strength. With this done, I recreated the top face plate, and made a bottom face plate, allowing you to mount both to create a similar look to the suggested look in his post.
You likely won't need to use all 4 screw holes if you're just holding some keys. I did Personally, but mostly because why not? Also, it's a snug fit, if it's too tight for you, you can either file down the top/bottom a little, or increase the size by around 1% (I've tried .5% and had good results) Since these parts fit together, I'd suggest printing at a higher resolution to get some clean fitment.
For infill, I went a bit high (50%) to lend more strength to the hooks where they connect to the base. This may not be necessary however, only time will tell, but for functional items I'd rather be safe than sorry. The bottom cover will help with this as well, once it's installed and snug.
I marked the top/bottom covers on the reverse side with markings to show their orientation, so you won't try to put the top on the bottom or vice versa (they may be similar enough to where it won't matter, but I am not sure.) I am currently printing a new copy of this with better filament to get a better demonstration image, and to hold the whole family's car keys, so images coming soon!
This is a work in progress. I am still tuning the band so to speak, going for the perfect fitment, so hopefully I'll get it dialed in just right, where very little adjustment is necessary, if any.