I've bought 6 cases so far:
LG V20 Case,APLUS [Shock Absorption] Drop Protection Hybrid Dual Layer Armor Defender Protective Case Cover & [ Free 9H Tempered Glass Screen Protector] for LG V20 (Black) RETURNED, felt very cheap and slippery
LG V20 Case, POETIC Revolution Series [Premium Rugged][Shock Absorption & Dust Resistant][Heavy Duty] Complete Protection Hybrid Case w/ Built-In Screen Protector for LG V20 (2016) Black CURRENTLY USING but a bit bulky
LG V20 Case,ANLI(TM) [Shock Absorption] Drop Protection Hybrid Dual Layer Armor Protective Case Cover for LG V20 (2016 Released) Black RETURNED, felt very cheap and slippery
LG V20 Case, VRS Design [High Pro Shield Series] Brushed Military Grade Protection with Metal Kickstand (Dark Silver) RETURNED, felt very slippery
OBLIQ Flex Pro Case SHOCKPROOF Slim Light TPU Drop Protection Cover for [LG V20] ON THE WAY
the 2 on the way are very thin and just hard rubber, I wouldn't use them until I get a good screen protector...
This one is interesting it has a front cover on it:
https://www.amazon.com/Revolution-Absorption-Resistant-Protection-Protector/dp/B01IRR0VCE
Will Up date this as I receive other cases.
First case was the Incipio DualPro Case - Returned it, slipped out of my hands to easily and no real grip. Also, the area around the camera screen didn't feel like that there was enough lip to have decent protection. The headphone port opening was large enough for IEMs but not large enough for the plug to my DT 770s, charging port opening more than enough room for any cable. Another upside to the case was that the volume buttons worked well and were very responsive.
Exchanged the Incipio case for an OtterBox Defender Series and there seems to be a build issue with this one compared to the other OtterBoxes I have used. There is a noticeable gap between the screen and the built in screen protector, enough to cause issue with using the keyboard. This gap starts about middle of the screen and continues down to the bottom making buttons on the bottom difficult to use.
Also, the protection is different from the OtterBox I have on the LG G5 around the camera area. For the V20 Imgur it's plastic, on the G5 Imgur was rubber, not sure how that will affect shock protection around the camera area. Compared to the one I had for the G5, the one I got for the V20 feels cheaper than it should. Also the volume rocker buttons are not very responsive and sometimes have to push in a lot to get any connection to the phones buttons.
Just ordered the POETIC Revolution Series and should be here Tuesday.