Omnisphere

[Biome_Digital]

For something to be like Omnisphere it needs to be able to use samples and synthesis. I would say something like Pigments or Avenger would be good a alternative.

Here's some Granular Pads in Avenger as an example:

[Sera]

I would maybe suggest a native instruments kontakt bundle for realistic sample libraries. The sounds are usually pretty damn good, tho kontakt can be a bit annoying to work with