If you're going for a spinning coin that looks 3D in Spine, I’d suggest first looking at some visual references. Before diving into Spine, it's a good idea to think about the overall style of your game. Is it cartoonish, realistic, fantasy-themed, or something related to gambling? The type of setting will influence how your coin should look in terms of shading, shape, and spin behavior. When I was working on a project with a similar theme, I checked out some examples at https://somagyarkaszino.com to see how coins are used in animated effects and bonus visuals. Searching for “2D coin spin animation” or “coin sprite sheet” based on specific themes can give you much better ideas than using generic references.
Back when I needed a similar effect, I found this guide really useful:
They explain how to simulate 3D by distorting shapes and adjusting timing.
Also check out this blog post:
http://esotericsoftware.com/blog/spine-tips-simulating-depth
It helped me understand how to fake rotation using squash/stretch and subtle mesh warping.
Lastly, if you have access to drawing software, you could export a few frames from a 3D tool (like Blender or even a coin spin GIF), trace over them, and import those as separate images in Spine for frame-by-frame style. This gives a really clean result if mesh warping is too tricky.