I have standard cheap but nice and sturdy square metal tube and glass shelf big box store racks I bought a very long time ago.
One tall and two TV sort (one TV sort holds my two turntables)
The big upgrade to them happened last year when I added butcher blocs under each and every component. 20 Butcher Blocks in fact..(that includes Butcher blocks on floor under amp and power conditioners. and some Butcher Blocks doubled up particularly under amp and turntables.
This is just to say there could be an upgrade path keeping what ever shelving one has, but adding good solid Butcher Blocks under equipment.
Mine definitely improved the sound.
In addition I added bits of Exotic wood as footers, but that is another story