We've got a couple of "list" questions asking about official D&D 5e content and resources already.
Would a question asking about available classes published by WoTC, including archetypes/subtype (preferably including Unearthed Arcana if that doesn't put the question in jeopardy), be appropriate to ask here following the same principles made on the Where to find races and classes in 5e meta question?
There are a few problems I can see that might make such a question an issue and too broad though.
There are a lot more class options scattered throughout the available resources than there are races.
The inclusion of Unearthed Arcana material expands this list tenfold (I would really like to include this though, if possible).
New Unearthed Arcana material gets realised every month(?) or so which means the question would need to be updated more frequently than the one about races.
I don't believe we have these sorts of questions for previous editions (there is this one for 3.5e that is closed as too broad and heavily downvoted, though it is asking about both races and classes). Focussing too much on 5e could open the door to these types of questions for previous editions (which may or may not be a problem).
I'm not sure how well such a question would hold up over time.
The question is here: What are the official, WotC-published classes and subclasses in 5e?