At the end of last year Bakker Elkhuizen introduced the The Egg Ergo Mouse Pad as a mousepad that should be both comfortable and ergonomic. This is supposedly achieved by the special shape of the pad and also the material that's used, which should keep your hand and wrist warm.
The egg shape provides more space in the area where you make the biggest movements with the mouse, and a narrower space for where your wrist is. This makes it so there's only one good spot for your hand and mouse, without limiting any common or natural mouse movements. By putting the mousepad at the correct distance from your keyboard, it will help facilitate an ergonomic posture at your desk, according to the manufacturer Bakker Elkhuizen.
The insulating material of the mousepad consists of rubber sublayer and a fabric top side which keeps the hand and wrist warmer than the cold surface of a desk. This should promote bloodflow and prevent your wrist from getting stiff.