Technically there’s only a finite amount of pages since there’s a character limit, so you technically could search all of them and see which ones have been edited and which haven’t, but good luck even getting past five characters long within your lifetime
Even if you restrict it to just lowercase letters (which misses a lot of pages), you probably won’t even reach ten letters (I edited every single previously unedited two-letter page using a script a while ago though)
So I assume this means there is no list of existing pages? (Since that’s what I was asking for, not hypothetical pages)
The most complete one I know of is one I made using a crawler-like thingy a while ago and it did contain some interesting pages I didn’t know about but it’s safe to say it’s nowhere near complete. I also still find random pages I never knew about monthly, so I don’t think there’s any way to get a complete list.