I have spent the last three weeks trying to make realistic  volumetric 3D clouds in Unity.
I found some free clouds that were not fluffy.
I made some volumetric clouds in Unity but could not make them fluffy.
I make some fluffy clouds in Blender with cloud generator (www.youtube.com/watch?v=EpGdRJFPVEI) that would not go into Unity without losing their fluffyness.
Finally I found this excellent free cloud toy (assetstore.unity.com/packages/tools/particles-effects/cloudstoy-35559).  As I didn't have the source code, I made a script that detected when the clouds were spawned and then added rain to them.
Next step: realistic looking dry stone walls.

I went to London to the BAFTA Young Games Designer finals and had an amazing time.  There was a fabulous ceremony and a really good talk by a developer.  It was so exciting!  I didn't win, but will have another go next year.  The winner in my category, Maggie by Harry Thurston, is really good.  You can download it from ygd.bafta.org/competition/competition-news/2018/maggie.