Transport, comms, banking, and information technology, tend toward monopolies.

Consulting is a mixed bag -- if you're relying on creativity, not so much, but if you're relying on marketing and business contacts, both of which are far more a network effect (with strong lock-in elements), yes. Contrast your typical small-gig design shop vs. the Big Declining n Accounting Firms, or IBM and Oracle (consulting / business services).

Retail can be local (small effects) or global: large grocery stores, WalMart, Amazon.

There are other effects as well. I've been curious about Maersk's adoption of ultra-large cargo ships, even as shipping volumes have been falling. While there's a financing-design-build lag, there's also the possiblity that having and operating a large ship puts pressures on other operators -- if you're operating and loading, you're taking cargo which would go onto smaller vessels.

It's complicated.

Part of this also plays into concepts of what and how technological mechanisms actuall function: https://ello.co/dredmorbius/post/klsjjjzzl9plqxz-ms8nww

I'd include among "network effects" urban and even empirical structures.