Typical bar tapes are too thick for bar ends. End result will be UGLY(I tried).
Outer grip for tennis racket works fine. They are inexpensive and come in various colors.
Hockey tape might work as well.
If you have long bar ends you can use track grips(works great).
Your hand numbness problem might be caused by the grips being too plush.
I find plush grips are great for a short ride but, I always get persisting numbness for rides longer than 2hrs.
I replaced my grips with thin flange-less BMX grips and the numbness problem went away.