I had to clean up a bit here. Please people, no more 'I saw a documentary once' or 'through my years of reading'. Back up your claims with sources. Post comprehensive answers to the question. Not anecdotes or trivia.

It's always possible, and I believe there probably are some smaller cultures we haven't yet uncovered. This goes more into archaeology, but as an example, Gobekli Tepe in Turkey wasn't discovered until the 1960s. It wasn't until the 1990s that archaeologists appreciated how old it is. Similarly, early Russian cultures are just being uncovered now, after difficulty under the USSR. As an example, Khazar sites are just now being explored in the last twenty years.

There is also a big effort now in northern-Canadian archaeology. We don't know much about the early peoples who lived there. I had an archaeology teacher who wrote a book on his discoveries. I'll see if I can find it.

Now, it depends what you mean by "advanced." I think we are likely to find civilizations that we know little or maybe even nothing about, but they are going to be "normal" for their times. I'm not sure if you are trying to provoke an Atlantean response, but the answer is almost 100% no. It would be foolish to count everything out, but there is no reason to think any pre-historic civilization could have been "advanced."

TL;DR: Probably things we don't know about, but not more advanced than we would expect.