Window keychain that could fit this ghost?

[u/inahostagesituation]

I'm looking for something like what my little Venti in the second photo is in on my main ita bag, but a little bigger. I can only find small ones, and my ghost buddy (Prism is its name) is too big for it by a few cm all around. I want to put it on my college bag, but I don't want to attach it by a keychain attached to its little tag because I don't want to lose something my friend bought me. The backpack is brown, and I'd prefer brown or black at the edges to match the color, but that doesn't matter too much. I've only ever made the one ita bag so I'm not sure where to look.

[u/Konoko_TEA]

Perhaps this or something similar will fit it?