I took the existing Witcher medallion model that I found here on Thingiverse, and fixed the loop so you can wear it.

True, it isn't exactly like the loop on the witcher medallion in the game, but if you have ever tried to wear that print, then you know the loop doesn't sit right. It puts the necklace at an angle.

This loop allows the medallion to sit flush on your chest when worn with a chain. It prints good at regular size but when you scale it up too much, the base starts to have problems printing. I think it isn't exactly level at 0 degrees on the Y axis. If you figure it out, let me know, cause I'd like to print a huge one.

I modified this in Cinema 4D, and exported the stl file from the 3D Wox Desktop app.