As far as sheets go, if money is no object, these are absolutely fantastic: https://www.sferra.com/products/sferra-giza-45-sateen-collection https://www.sferra.

As far as sheets go, if money is no object, these are absolutely fantastic: https://www.sferra.com/products/sferra-giza-45-sateen-collection https://www.sferra.com/products/sferra-giza-45-sateen-collec.... Warning, a full set will come to about $10,000 (though they do periodic 20% off sales). I also got a duvet from them so that the duvet cover would match the size of the duvet. Also, they'll customize the sheets to your mattress if you send them measurements. I haven't found any other way to get a tight-fitting sheet, as it seems that king mattresses and sheets have a wide range of sizes, and the last thing you want is to splurge on amazing sheets that give you a bad night's sleep cause they don't fit properly.