SVS Subwoofer Isolation feet compared to standard feet. Looked promising, but made little to no difference in rattling on mantle/walls/etc. : r/hometheater
Amazon.com: MYOYAY 2 Pack Subwoofer Speaker Stands 14x14inch, Isolation Stands Speaker Isolation Feet Subwoofer Audio Isolation Platform with Fixed Copper Nails for Standard Speaker(Black) : Electronics
Amazon.com: SVS SoundPath Subwoofer Isolation System (4-Pack) : Electronics
SVS SoundPath Subwoofer Isolation System - Black Box Pro
Auralex SubDude II Subwoofer Isolation Pad | Sweetwater