Hawkins’ has developed the Edenverse over 3 books, but all of those are a niche product. Hawkins has a couple of bad habits that I don’t think help grow the line as much as it could i.e. padding trades, pricing.
Mignolaverse is the big one I’d look at, there’s a consistent branding on those books so as to tag the customer that they’re part of a bigger whole, with signposting to those other pieces in each volume. But, this is generally focused on one genre.
In some ways there’s no magic to what Mark has done with Millarworld except he’s worked with the best people he possibly can, on excellent collaborative terms that I think are unmatched and he’s backed up his motormouth marketing (mods, I think that’s a fair description) with delivery to match. I know his marketing style - Stan Lee inspired? Hmm, might be - drives some people nuts, but he’s had a very good hit rate on all the books.
If you want help with that or more recommendations than you’ll know what to do with, the Trades Thread (and its many predecessors) beckons.