Different Versions of RingCentral?

Is there a full list of all the different versions that Ring Central offers?
We are looking for the one with the most features.

Our current version has a limit of max 15 wait time on queue, which obviously does not work when you have X callers calling in at the same time.
I somewhat recall seeing that there is a version of Ring Central that is a full blown call center application which would allow longer queue wait times.

Looking for some guidance.
Thank you
Felix