The Abell catalogue is an almost complete catalogue of approximately 4,000 galaxy clusters.
https://en.wikipedia.org/wiki/List_of_Abell_clusters
I have some Abell cluster on my extras folder, but these clusters are in and around the Milky Way.
Is there a more or less complete Abell Clusters add-on?
By the way I've just made an Abell 370 add-on, but I'm not sure about the radius of it. A few hundred kiloparsecs maybe? Or more? A megaparsec?