although there is a variety of configurations, the one probably seen used in industry the most is 3 ph 480/277Y, with a customer owned X-former to step down to 3 ph 208/120Y. A dual utility set-up could be arranged depending
on the particular utility involved.
I would say that Wye systems are probably the norm, Delta's have had their hey-day, other posters may differ due to their area's utility.
there are some existing 'strange' ones, such as a corner grounded delta that are allowed to be left operating, but this is only for economical reasons. To my knowledge they do not rate any historical classifiction that justifies thier existence.