There are two ways you can make your own personalized pickup covers.

One involves polymer clay, which you roll out, cut/mould to shape, then bake in a oven till it hardens.....you can do all sorts of things with this stuff, like texture it, put glitter etc in it, they also have Metalic colors..... but it's trial and error territory till you get exactly what you want, as it shrinks a bit when baked.
I recommend KATO brand polymer clay for this, as it's really tough once baked, as it's designed to make wearable jewellery.
https://polymerclay.com.au/clay-craf.../kato-polyclay

The other method involves making a mould of the pickup cover you want, then using casting and embedding resin to make the covers.
Best stuff to make a cast with is this reusable Composimould
http://composimoldstore.com/