Tagging is a better solution than color coding imo because easily discernible primary colors are limited.
For example I can tag [Fender], [Marshall], [Mesa] then search, organize, hide, etc. by tags.
Multiple tags per amp will allow even faster search if you want further organize things by gain, favorite, whatever, a Tag Manager and Search will be needed, things can get a little complicated.
On a second thought, we don't have thousands of models like captures so just one tag will be enough to display a shorter list without scrolling.
This is a purely Axe/FM Edit function, because entering letters on the hardware will take far longer than just scrolling through the entire model list.