They're, quite literally, the same. You have the Greys, which are you stereotypical big headed little guys with the big eyes who cloned themselves into a pickle, you have your Pleiades living Aryan Nazi propaganda looking ones that are allegedly the good guys (coming from people who also believe in the The Protocols of the Elders of Zion), you have your lizard people mimicking humans (allegedly evil and who are the puppet masters in today's political climate), etc. They build the pyramids, or the pyramids are landing places for their ships, and they ruled and guided us in ancient times, and now we have them rule us in the shadows. It's all a string of the same bullshit stories they are making up for decades now.