Have you considered Umbra Mystic ? Together with Rancor or Brilliant Halo you can pretty much keep your commander from ever dying.

Alpha Authority is pretty good too, I know it overlaps with your commanders ability.

Thanks for checking out the deck.

I had Umbra Mystic in a previous build, I took her out in favour of Gaddock Teeg . Mystic was only ever a one off protection as she would get caught in wrath effects, Teeg serves as better protection by preventing most wraths and he can be tutored off of Green Sun's Zenith .

I find Alpha Authority just dosen't do enough. I already have four ways to make Sigarda completely unblockable and of those two pump her and one draws a card.

Definitely recommend Privileged Position . It's one of the staples of G/W enchantments. I mean, having enchantments paints a target on you, but at least PP protects you. It's pricey, though.