Vector frame inspired by Celtic knot designs.
Here's a simple example using a gradient map to give the frame a metallic look. I used the official ゾウノセ gradation set which you can find here (https://assets.clip-studio.com/en-us/detail?id=1826135).
For a more realistic effect, I'd suggest shading with a multiply layer, I'm just lazy so I didn't do it here. 🦥
You could also use this frame as part of a tapestry or even as a comic panel if you're feeling really wild. Knock yourself out!