So far these are the cases that I like the most.
1. OnePlus 6 case, Sucnakp TPU Shock Absorption Technology Raised Bezels Protective Case Cover for OnePlus 6 smartphone (Black)
2. OnePlus 6 Rugged Case, Poetic Revolution [360 Degree Protection] Full-Body Rugged Heavy Duty Case [With Tempered Glass] for OnePlus 6 Black
3. OnePlus 6 Case, Poetic Guardian [Scratch Resistant] [360 Degree Protection] Full-Body Rugged Clear Bumper Case [With Tempered Glass] for OnePlus 6 - Green