Is there a word we can use to refer to big clusters of clouds, attached or unattached? I am thinking there might be a word, but I've never really heard of words related to cloud being used in any book I've ever read. I keep seeing words related to a type of clouds, but not related to a group or cluster.
There are many choices.
If you search there with the phrases
a NOUN of clouds or
the NOUN of clouds
you will see many options (ranked by frequency).
These are a few from the first page: mass, sea, line, blanket, layer, canopy et al.