I'm still a complete novice with photoshop. However, I started fiddling with the gradient tool and ended up with some pretty (if generic-looking) textures.
this one in particular reminds me of raw silk, and I can't help but like the
crumpled paper I ended up with.
Velvety 1
Almost more like silky water
An explosion of jewellery-box-stuffing
There are a few others but they're all extremely similar so probably not worth linking. Maybe they could do for sig bases?