The bonds of blood can be quite strong in any family, but just imagine the bonds between souls of different life forms. They can carry over from one lifetime to the next. In examining the stories of various contactees with alien groups and individuals,  I discovered that bonding of one kind or another was a common factor in most cases.

Here's my top ten list on this subject:

1. Alex Collier: Alex is a noted researcher into the different kinds of alien races which have visited Earth over the last few thousand years. He has worked closely with Michael Salla who helped develop the subject of Exopolitics. Alex began his association with the Andromedans when he was a child. Apparently, he was part of this group 62,000 years ago in Lemuria. There are many videos of Alex on Youtube, but the link with his name is the best.
2. George Van Tassel: He was the first person to contact "Ashtar and The Ashtar Command". He was also the first person to give UFO conferences for contactees and other believers in the 1950s. The belief in Ashtar seems to be a new age concept of the Second Coming of Christ and the Apocalypse.  
3. Simon Parkes: This was another story of a bond to a brotherhood that goes back earlier than this life. This time it was with "The Mantis Aliens" who treated Simon with a great deal of respect and affection. One of the ETs, even identified itself as his mother. This wasn't just a contact case. Simon's soul was transferred to a Mantis body where he operated as one of them. Needless to say, this didn't bother him at all. He fitted into this society very well. 
4. Charles Hall: He was just an enlisted man who was chosen in 1965 by "The Tall Whites" to be their pet. Over the next two years, he discovered that the aliens liked to raise their children in arid deserts and they liked to entertain themselves by gambling(i.e. Las Vegas). This is first indication that Earth is a desirable spot for alien tourists looking for a good time. Part of the entertainment is probably having sex with humans.
5. Bob Dean: Ever since he was snatched out of deep water by invisible hands at three years of age, Bob had something protecting him from death. This protection was in the Korean war and Viet Nam war as well. He doesn't name the beings responsible, but he stated there was a powerful spiritual presence there. Project Camelot did three or four interviews with Bob, check them out. They give more background on his religious beliefs and experiences.
6. Mark Richards: His story sounded like "John Carter on Mars". He fought with "The Earth Defense Force" against hostile reptilians on the red planet. Amazingly, Mark is protected against assassination by a raptor buddy that he met on Mars. Luckily, the raptor has given up eating people or Mark could be on the menu for their next lunch together.
7. President Eisenhower: Ike met two or three times with different ETs. Unfortunately, he signed an agreement with the wrong side. When you're scared, confused and unenlightened about ETs, it's difficult to think clearly.
8. George Adamski: His photos of spaceships were never debunked. Supposedly, he was the first human in the 20th century to be given a free ride in a spaceship. He was like a kid in a candy store and that's why the aliens probably liked him.
9. Billy Meier: The alien (Pleiadians/Plejaren) he met when he was a child was looking for converts to his non-religious religious views. Billy's website is mind-numbingly complicated about these spiritual precepts. 
10. Betty Andreasson Luca: It started as a routine alien abduction by the Grays, but ended up with an encounter with "The One". This could have been a traumatic experience similar to Travis Walton's abduction, but it changed into a positive spiritual experience because of Betty's Christian religious beliefs.