Rubber Nose Pads

Most nose pads for eyeglasses are made of plastic or silicone. This provide a slightly flexible surface, but their main advantage is mostly the fact that they can be transparent. However, if appearances are less important to you than comfort, rubber nose pads offer a softer surface to rest against your nose.
Rubber Nose Pads:

Rubber Nose Pads pictured: Bolle Replacement Nose Pads.