Got a chip in the powdercoat from the sidepull brake and started thinking it needed something like this:




Which I made from one of those pump-pegs that had a plastic L-bit sticking out of the hole; pulled out that bit, stuck a grommet in the hole.

Or just don't let your bars turn enough to let the brake hit the downtube.

I use clear, self-adhesive bumpers. Stick well, let the color show through, cheap, effective. Vast array of shapes and sizes.

Some brake adjusters have a rubber bumper to prevent frame dings:



failing that you can probably fashion your own rubber bumper out of clear hoses.

BF member jamesdak turned me on to these. They come two to a pack:

https://bikerecyclery.com/barrel-adj...ed-blue-green/

You can get generic adjusters that they will fit on Ebay.

They're not really designed to prevent frame dings, however; they're to provide grip to turn the barrel adjusters.

https://www.peterwhitecycles.com/tout-terrain.php

Pretty cool, in colors for "aficianado's."
I'll have to get black until I can age into a Buick and colored ones.
My last set came from Menards.
They have little bins you can waste tremendous amounts of time sorting through.
But stuff is there.

I pimped my ride with some white ones.