 8.10.19  5:08 am x-ray, x-men, uberx, tedx, zanex, fedex, x marks the spot, spacex, xxl t-shirts, xxx, xoxo, my ex, y=mx+b, xbox, 400x microscope, x-cetera.  any more you can think of?
kleenex, iphone X, mac os X, final cut pro X, logic pro X, x-factor, x files