Ok, after playing for about a month maybe I have 3 characters full of items that I have stashed because I think they might be useful at some point. These are a mix between version 2.0 and 2.1. Here are all the items that I have found that have Druidic set affix on them with the Bonuses mentioned separately. My main toon is a rogue which I have played almost exclusively if that matters. I will be building either a Warrior or Wizard poison build once I accumulate more CS/MS.
None (I had no idea! lol)
Amulet x2 (One with Druidic Bonus)
Armor x2 (has Ignore Resist affix too which is really nice)
Armor x4 (has Ignore Resist affix too which is really nice)
Hope that helps. Based on a small sample size, the only piece I have with the Bonus is indeed an amulet. The Ignore resist on the armor is really nice so that should be one of your 4 pieces to get the Bonus. Other than that, I have seen no weapons for any class with Druidic on them. Can't tell if that is reality or just the small sample size.
Anyway, looks like I have a good stash to start my build with .
Good luck on yours ljyupe!