There are numerous enchantments that synergize well with Ertai's ability, such as Dreadhorde Invasion, which consistently supplies creatures to sacrifice to Ertai's ability
A free Char and two Lightning Bolts directed nearly however you want is great value, and can even be a great way to burn opponents down if they don't have enough creatures to hit
Fewer packs, but every single pack delivers at minimum one holo or higher rarity card
If you plan on testing this deck, I hope this article did a bunch of the legwork for you, and wish you all best of luck announcing Evoshock , Devo Spray, Pickup Devo Spray. If you have any questions, feel free to contact me on Twitter @zturchan, and I hope to see many of you at the upcoming Regionals in San Diego and Dallas!
The honest answer to that is a lot of different places. Not to stress the point too much, but the ramp effect is honestly good enough to see play by itself