You've named only a tiny portion with the most publicly recognized ones. More people usually know these ones either because they're the most recent (Inca, Aztec) or have familiar sites (Puebloan) or artifacts (Olmec). But the Americas are huge and people have been living just about everywhere on them for millenia. For instance, you only mentioned one people group from the Andes, one that rapidly became the dominant force on the continent for about 100 years. We know a lot about them because we have actual written records. But people have been living there for 6000 years. That's a lot of history, and it's only really been studied for decades. Ever heard of the Recuay? I'd doubt it- there's about one and a half definitive books on them and only one published full site report, both by the same guy. They don't even have an English Wikipedia article. But they were a major culture force that introduced elitle government to a large region of Peru between 200 and 800 AD. So while the number of entirely undiscovered societies is likely small, the number of known cultures whose extant research is limited is very large.