Incipio Plex Plus Glass
Incipio is a trusted name in smartphone accessories. They're part of the official "Made for Google" campaign, so you know everything from Incipio is certified by Google for the Pixel 2 XL.
This glass has a 99.9% clarity rating, oleophobic coating to prevent fingerprints, and a subtle curve to match the design of the Pixel 2. It comes precision cut with access to the dual front-facing speakers, and color-matched top and bottom bezels to blend in with the phone. It's expensive, but it comes from a brand you've probably used before.