The crop circle one is a confirmed fake. The creator admitted it plus it didn't pass video analysis.
The George Adamski UFO video well, the mere mention of his name and you can pretty much take it as red it’s a hoax.
Another Adamski UFOWTC UFO- some promo to do with the sci-fi channel.
Bulgaria video- suspected use of CGI
Anyway take a look at this UFO vid. Seems to be one of the best in the public domain. I don’t think it’s been successfully debunked but you know the score with videos; inconclusive etc
UFO at Nellis Air Force Base, Nevada, USA
UFOA desciption of the video (poor quality)
sightings