I ordered one of the carbon fiber+brushed metal look cases off ebay a month before I got the phone, since shipping takes forever. If you are apprehensive about ebay you can find listings for similar cases on amazon. Sorry, can't link anything yet...
Regardless, I had the same design of case for my previous phone, a Mi Max 2, and it dealt with many falls and has definitely saved my ZF6 once already.
I have also ordered a couple of the fabric back cases, and one of the cases with the "rugged shield" text, intending to compare and post about them.
As the case offering for the ZF6 hasn't been too diverse, generic chinese stuff is what remains. This case I got for now is at least good quality though, the buttons and holes for speaker, camera, fingerprint, 3.5mm jack, mics and usb-c port are perfect and fit is snug. Of course it's just textured rubber, but it improves grip and protects well.
Don't know about tempered glass protectors. I tend not to use them since as long as you do not crack gorilla glass and don't keep it in a pocket with sand, not even metal can scratch it.