I like these peel & stick sheets I get off of eBay. When you rub your finger across the felt, it does not shed off.
They are about 3/16" thick and the adhesive backing sheet is very easy to peel off.
I have placed them on all of my ultra-portables where there is not a lot of space/clearance for thicker pads. Changes the metallic clanging sound to what sounds like a stick hitting a hollow log.
On larger machines, I will stick 2 sheets together and then cut out the pieces from construction-paper templates that I make, first.
.