Which cone's or platforms have helped?

There are about a million different approaches - the "right" one is the one that works best in your own rig.
My present "digital stack":
one-box CDP on top - (no mass loading atop of it)
Orchard Bay titanium cones
Orchard Bay brass pucks
Black Diamond shelf (or Zoethecus Z-Slab shelf, both work pretty well, Z-Slab is less expensive)
Vibrapods
rack shelf (itself an MDF composition)

Have also used Black Diamond #3 &/or #4 cones, and Audio Point brass cones in this sandwich. O.B. titanium's are amazingly better, but are not longer available. I'm gettting some titanium Nordost Pulsar Points & DH Labs ceramic cones to try next, but so far the above sandwich has worked best for me. YMMV

Neuance shelf is a must!
Orchard Bay are second, EAR footers third.
Aurio's Pro, new found love.

Tom nice - what are Neuance shelves made from? I did a search and can't find any info on them.
My preference has been for brass or those ceramic like foot sanding stones. I prefer a cleaner sound. Sorbothane seemed to muddy up the sound which I did not like.

The interesting thing I found out about Vibrapods is to not necessarily use their recommended weight ranges for each model pod. There are so many other factors in the mix.

My transport is on the light end of the range recommended for using #2 Vibrapods. In other words I could almost use #1 pods based on their information. All I had were #3 pods, so I used them temporarily. I notice a bid improvement. I later picked up some #2. Expecting even more improvement, I was shocked that using the #2 pods sounded worse; actually no better then not using Vibrapods at all. So the #3s are still there.

So I can see why some would not think Vibrapods work well. Following the directions may prove fatal.

Sugarbrie what you said...
I've been aware of this too, & found that the Vibrapods need to be loaded basically at the midpoint of their weight range. Just requires some simple math to calculate where you're at. It's like the springs on a vehicle; too little weight-loading & you're bumping all over the place, too much loading & you're always bottoming out. At midpoint, you have some "spring" in both directions.
YMMV