I'm not a huge fan of cases but since the phone is new I did pick one up. I just went with a simple, clear case for $9. I like it as it adds a bit of grippiness, it's not too thick and it shows off the silver finish.

LG G6 Case, Trianium [Clarium Series] - Clear Premium Protective Case Shock Absorption TPU Bumper Cushion + Scratch Resistant Clear MicoDot Cover for LG G6 (TM000105)