Wernher Von Braun after coming here following WW2, when asked how he knew all of this stuff about building advanced weapons and crafts, he told them the aliens showed them. Then there's his leader Hitler who was an occultist.
An ex-chief of CIA said he had access to a room of boxes that most people don't and he said a box that said "Roswell" caught his eye. He wouldn't give detail but he said it basically confirmed what he thought and that it happened.
You've had astronauts claim they're real. Former astronaut Dr. Edgard Mithchell holds the record for longest moonwalk. He claims he was debriefed and that they're real.
Charles Hall an author who was in the air force, observed weather balloons, was given an award for surviving 35 attacks in vietnam, has a bachelors in thermal physics and a masters in applied nuclear physics... he claims to have met "tall whites" at a Nevada base out in the desert. Without going into every detail, a lot of his claims on what he saw there have been supported by others who have researched it. He even said they built bases in the mountains to house the tall whites and is off to the public. At the base he said they referred to the tall whites as "big sheep horn". Keep in mind, he made all of these claims before stuff like google earth existed. If you go on google earth, that location looks like how he described it including three white pods and they even title it "big sheep horn habitat". Back when they did a bunch of construction on the base, it was called the indian springs project and the contractor that won the bid for the job got 300 million dollars and had previously done a number of other projects for the government. Today, that 300 million is worth over 2 billion+. Problem with that is, when you look at the base and what is consists of it looks nowhere near that amount of money. On top of that, there were earthquakes taking place in the area during the time of the construction and not seeing the value of the money spent above ground, it could be as Charles Hall said that they had multiple housing areas for the tall whites in the mountains and the earthquakes were the result of drilling.
Charles Hall on actually speaking with the tall whites... he said the tall whites leaders have met with all of the high ranking government officials and would only make deals with the government if they felt they were getting the better end of the deal. The one thing they wouldn't teach us is how they travel. The tall whites told him that other types of aliens exist but earth is the only planet with intelligent people like us who are so close to animals. Riding them, eating them, having them as pets. When life becomes intelligent on other planets, they come to the conclusion that animals are stupid and kill them. They also said we'll eat anything including animals while intelligent life on other planets will only eat plants. They were also surprised by how well we bounce back from injuries and all of the stuff we can do physically as they're frail. Apparently they'll put themselves first at any cost because their numbers are dwindling.
Those are just some things I've read about recently. Whether it's true, who knows. Some of the people I mentioned you might find more credible than others. WVB's comment sure is something. I recall reading years ago about Mayan's learning everything from aliens as well which also made them advanced for their time. So the WVB comment I find really interesting. Obviously a former CIA chief and an astronaut with a PHD is nothing to scoff at. As for Hall's story, I just find it interesting even if he isn't as credible as the others list. He originally released the book as fiction but later on said it's real with only names and minor details being changed. Again, what makes his story interesting aside from actually claiming to speak with aliens, he does have a couple of degrees that are out of my wheelhouse and his claims all came before you could use google earth. The way he described everything checked out.
At the end of the day, I do think aliens are probably real(or demons acting as aliens if demons happened to be real) as there is too much info and what appear to be coverups. The problem is, you never know what stories are legit and which are made up. All you can do is hope you find someone with solid credentials and isn't using their credentials in attempt to profit off making bogus claims. There is some pretty damming stuff out there. Look at all the football heads scribbled on walls of pyramids. They can draw every detail as a person appears but failing to draw a circle instead of an an oblong oval/bean shape is where the artistic ability ends?
Whether aliens are real, at least I found it interesting and the possibility for now still exists.