I’ve cut small lengths of bicycle inner tube...couple of inches long...and pulled it up on my SureFire flashlights. Helps a little. I used an old tube from my road bike. Probably don’t want to buy a new tube just to cut up.
I also used Talon Grip on my Kahr pistol. It was OK as grip material. Lasted a long time, but got to looking worn, so I pulled it off. Seemed like good stuff at the time and stuck like a champ.
Thx for the inner tube suggestion!