I heard about someone making a Valkyrie deck with Cauldron Cookbook, but couldn't find a list so I came up with my own that took me from the final stretch through Diamond I to Masters this month (Oct 2018). I'm sure it could use some tuning, but here's what it did well:
Especially when I got cauldron early, I stayed ahead on tempo throughout most of my games which allowed me to have answers against all match ups, even allowing me to win against a few temporal control decks.
I only killed myself with a firebomb once, the rest of the time I barely got touched by firebombs, and if I did, it didn't matter due to the life I had. It's been said that the only amount of life you need to win is 1, so long as the opponent has 0 and, well, I've had that game.
Because of Cauldron, I didn't feel the need to rush out units - I could play a little control oriented knowing that I would have the advantage late game in most match ups.
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Dubious cards: These cards, while sometimes being useful, were most often swapped when it came to market time and it's probably no surprise: Geomar - I love him, but he's hard to play in a control match up unless you also have rolant's intervention and you have 5 power, Victor's Cry - I did swap this card out a bunch, but it's also surprising how often it won me games, so I may still keep it. +5+5 is just unexpected and very useful against big time fatties if you don't have a vanquish in hand. Righteous Fury - this won me my first game with the deck on Icaria, but other than that it never came up. The idea in adding all these cards was that I would need to get my life back from firebombing myself, but as I said, I rarely got burnt so they could be swapped around.
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Overall, a fun deck and I feel like I can say that Cauldron, so far, has been a great card is this deck with little to no drawback that helped me curve out and control my games. Have fun brewing!