This is a test with low light - scene is lit with only one light stuck in the sphere (which is solid - material settings are basically the "milk" settings taken from the demo shaders) and a low-key hdr from the outside.
You see the beauty with glare and reflect pass added on top.
Renders obscenely long (this one has about 900 passes) even with denoising.
Of course this approach is impractical, as one would normally render a lighter scene and dim it down afterwards or put more invisible lights into the scene, but are there tips for tackling a scenario like this, meaning: Corona settings?