Under a past amplifier, I used a bamboo cutting board that had a groove around the the edge( to collect juices). In that groove I glued some fishing, soft rubber worms. Turned it over so the worms were all that touched the counter. I thought it made a noticeable difference. The amplifier I have now is to heavy for that and I’m going to get some Isoacoustics Indigo isolators.
YRMV