Kylie Jenner
We already know that Khloe is a believer, but it looks like the youngest of the Kardashian-Jenner Klan, Kylie, does too. She told Cosmo that she had been to the highly restricted Area 51 and spoken with alleged alien abductees. She added that she finds aliens super interesting, but is also afraid of them.
Source
//www.ctvnews.ca/entertainment/kylie-jenner-says-she-believes-there-s-life-on-other-planets-1.2194346