White made the most sense for this battle because of the abilities we chose
Unfortunately, MTG Annihilator cards dont come cheap
Despite lacking the Madam Mim bounce package that once made the archetype great, Amethyst/Steel just has so many handy tools available to it to make it strong, and the latest set gave the deck even more to work with
I think most peoples' minds will jump to Craterhoof Behemoth, who certainly takes the true crown for Green finishers, but it's wild how ubiquitous Avenger has been since its release
The two most famous being Lightning Greaves and Swiftfoot Boots which will grant the creature they are attached to Shroud and Hexproof, respectively
Alternatively, think of Purphoros as Fires of Invention that is also the Cavalier of Flame to haste in any giant monster