Somebody has actually managed to sell several pairs of $20,000 speaker cable. Support and popularity are indicators of superior marketing, not necessarily of superior performance.
All aftermarket mats that someone was trying to persuade my friend to carry in his store. Various types of foam, sorbothane, felt, glass, plastic and some others I can't recall. No stock mats.
This event predated perforated shelf liner and attempts to machine mats out of solid carbon and exotic metals, so it can't necessarily be applied to any of those.
BTW, my friend did eventually stock several of the mats and put them on his in-store demo tables, but he picked them by reading audio magazines to see what was popular and therefore more likely to sell. I don't think he ever put any of them on his own tables at home.