Spigen NeoFlex 2-Pack
Another trusted brand when it comes to smartphone accessories is Spigen. And while they were the original Glas.T all glass screen protector brand, their best option for the Galaxy S8 is the NeoFlex film. Again, because glass doesn't install properly for most Galaxy S8 owners, they offer a film protector.
The Spigen NeoFlex comes in a 2-pack for just $7.99 and is a self-healing and fingerprint-resistant film that's easy to install. The company claims each installation is bubble free, quick, and should work with cases.
Instructions on the product page do mention small bubbles or a "rainbow" effect on the film could be visible at first and should dissipate and disappear once the film dries and the application process is complete. With over 300 positive reviews, this is another we can recommend.