Some pens let you swap out the grip area of the pen to customize the feeling of the pen.
This pen comes with several different grips or can be used without a grip.
Hagurumado woodcrafts (https://hagurumado.com/) offers wooden grips for select models of Wacom pens.
I have this model (https://pinion.thebase.in/items/26608192) shown below which I use with a KP-504E pen. It was easy to swap out the original grip. The wood adds some "warmth" to the touch and just looks very elegant.
Model: "Wooden Grip for Wacom Pro Pen 2 (KP-504E) [Thick Bodied with Button hole]"
Some people make their own grips using
Raquetball tape
Hockey tape
Suguru (See this reddit thread)
Yarn
Here's an example of someone using yarn to make a grip. (from this reddit thread)