Is the floor of your listening room wooden/on wooden joists or poured concrete slab? Are you thinking of speakers or everything else?
For concrete slabs you're best off spiking (not isolating unless you live next to a stamping plant or freeway). I use a leftover piece of shelving spiked into my carpeted concrete slab for my simple system (sans speakers), located 3 feet from front wall. Gear is removed from a room bass pressure point (intersection of wall/floor), eliminates bunched up wiring, makes connections easy, and doesn't block the soundstage. You could find this idea used years ago and I thought it was too "long haired" for me, but with loss of my own hair plus a dedicated room and use of remotely controlled source and DAC/preamp it works.
For really soft wooden floors consider wall mounted shelves. Isolating vibrations from loads placed directly on a wooden floor is a crap shoot. It's gets highly mathematical to try analyzing comparative resonate frequencies of the floor, rack, possible added footers, and equipment. Most footers are way, way, way too stiff to be effective (not compliant enough for the weight of pieces of audio gear). Rules of thumb: heavier the support/gear the better; extremely soft supports work best; ignore supports that try to address horizontal movement (useless). I prefer to float speakers on soft floors to keep from turning the floor structure and the space below into a huge resonator. I know of no effective isolation for turntables on soft wooden floors.
Putting your equipment (except speakers of course) in another room, closet, or even on another floor can be very effective.
