My understanding is that the great majority of the New Kingdom pharaonic tombs have been located, and a rather large portion of the ones from other periods. The Pharaohs, of course, comprised something of a minority of the total population and undoubtedly only a small minority of burials, even elite burials, have been discovered. I wouldn't hold my breath for another Howard Carter moment, though--Egyptian tombs have been picked over for literally thousands of years.

That being said, of far more interest and importance given our present state of knowledge are the settlements, because Egyptian archaeology is notorious for being tomb heavy and settlement light. It isn't precisely true that Egyptology is a discipline without settlements, which is its stereotype, but as a general rule the sheer density of population in Egypt means that practically every ancient settlement has been built over and rebuilt over for millennia--and, of course, covered by the annual Nile floods.

So if you are wondering about whether there are any tombs filled with gold and jewels, there probably aren't many left. If you are wondering whether archaeology still can teach us about this fascinating civilization, the answer is unambiguously yes.

I apologize if this comment is against the rules but piggybacking onto this question, what about other ancient civilizations?

Here's a great example of how the study of ancient history can change and evolve: Just this year, archaeologists discovered a previously-unknown (although its existence had been theorized) "lost" dynasty of up to 16 Egyptian pharaohs at Abydos, dating to the Second Intermediate Period (c. 1650-1550 BC).

And here's another article about how archaeologists discovered a tomb used for the children of royal families. All of this is just to show that we never really know what we don't know, and that there's always the potential for a really dramatic discovery that changes how we view antiquity.

Piggybacking on this question, are there estimates of how long ancient Egypt was around? I've heard that Egypt is an older civilization than most modern estimates (based on things like water erosion on the Sphinx), can anyone with more knowledge comment on that?