Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Why Draven Support?
(Seriously though, this is a semi-troll guide, read an actual guide and merge this one with that).
Very standard, nothing very notable except Oppressor and Bandit.
Oppressor - With your frozen mallet, you should always be slowing them, so you always have 2.5% more damage.
Bandit - Basically more gold the more fed your ADC is. Its just like the ancient coin item.
Now, this is the interesting stuff.
Ancient coin is the only real helpful starting support item, and the mana regen could be useful at times.
Iceborn Gauntlet's spellblade will be activated pretty much all the time because you should be spamming your w like there is no tomorrow. The extra slow can also help kite.
Frozen Mallet is your main CC tool, usually in the laning phase because you won't be using Iceborn Gauntlet's spellblade much during the laning phase.
Berserker's Greaves are just good for any adc-like champion. Also, the furor is good for kiting.
Locket is just a generally good item for suppports with its aura and is active.
Bloodthirster has good lifesteal, and the shield you gain can be useful at times. You can switch it out with Blade of the Ruined King if you want.
That is pretty much the only difference between other Draven guides. Look at other Draven guides, and follow those, except use my items/masteries.
I may add more in the future.
Any tips/suggestions please notify me.