Law of One is probably the most comprehensive source in addition to the two I linked my longer comment. It's a series of conversations with an alleged 6th density entity who explained much of this stuff back in the 80s.

NDEs are also good as they're first hand accounts. Here is the famous case of Howard Storm talking about a vision of Earth a few centuries from now that he was shown while on the other side.

Law of One is probably the most comprehensive source in addition to the two I linked my longer comment. It's a series of conversations with an alleged 6th density entity who explained much of this stuff back in the 80s.

NDEs are also good as they're first hand accounts. Here is the famous case of Howard Storm talking about a vision of Earth a few centuries from now that he was shown while on the other side.