Volibear is a big beautiful bear and I'm a support main. More viable now that hexflash exists.

Aftershock is a no-brainer for a tank with cc. Demolish always feels satisfying and helps you get those plates and knock down turrets. Bone plating helps you survive in lane against a ranged ADC who might want to do damage any time you approach the wave. Overgrowth gives you bonus HP, and more HP makes w do more damage. Extra CDR is always good, and hexflash is the most important part of Volibear support, as it lets you jump out of brushes and alcoves right onto unsuspecting targets.

Relic Shield for your AP scaling, DMP gives speed and armor and extra damage, Zeke's gives the ADC more damage in teamfights, Thornmail is more armor and deals damage back to the enemy ADC. Pick the better boots based on the enemy team being AP or AD. Take Abyssal Mask if your team is heavily AP, Spirit Visage if the other team is AP, Knight's Vow if your ADC or Mid are fed, Sterak's Gage if the other team is burst heavy or if you're fed.

I've played Volibear support since season 6, and I just love being a bear and running straight at my enemies. As I've gotten more into playing ranked seriously, I've found that Volibear is not a good first pick, but he can be a nice counter to hook champs. If you have your passive up, and the other team is pushing, you can let yourself get hooked and then flip the ADC and win the fight thanks to your healing. Best counter to Pyke especially, and also good for flash interrupting Yuumi from getting attached.