This is my first build please be kind.

This build is focused on dominating top with your high hp, regen and speed, The more hp you have the better. Not only is it good for tanks but it is good for your W since it's active scales with health. The speed quints is to compensate for the lack of boots for a while and to catch up to those super quick champs or the ones with slow. With this build i have not lost a single normal game. I dont know how this build will work in ranked but feel free to let me know in the comments if you happen to try it in ranked.

I picked these runes for tankyness and a little bit of damage.

Quints are for catching up to those annoying champions with slow and very fast movement.

Glyphs and seals complement your W and your tankyness.

and Marks are for a little bit of damage and A.speed that you might need.

Pro:
Passive and E makes volibear hard to gank.
Quick M.speed and A.speed.
Warmogs and Atma's make your health and damage awesome.
Nice AoE and CC.
If you can get alot of CS you are basically unstoppable.
Combined with Sona ult or Viktor's stun your ult does alot of damage.
OP at the moment.

Con:
Low health and damage early game
If you get ignited your passive is significantly weaker makeing you more easy to kill.
You might get yelled at by the enemy team for being OP.
No good escape ability but again thats what the speed quints are for.
Hard to farm at first but gets better later on.

Basic tank masteries no big deal.

End summary.

I think volibear is a very strong champion and i predict a nerf in the very near future.
With lucky games you dont even need ganks from your jungle but like i said only if its a Lucky game.