Context: This is a deck designed for a Progression Series with four close friends. I won the first week with it. I hope to contribute to some sort of resource for similarly-minded people with this since deckbuilding with almost no playables is... unexpectedly challenging. You struggle to fill in the remaining spots very quickly. I hope to provide a few guidelines and am open for criticism to improve in the future.
The concept of the deck is fairly simple: Sit behind 2k defenders or try to establish a board presence with Witty Phantom, Trial of Nightmare Uraby or Skull Red Bird. Eventually, go into your tributed guys + proper field spell and dominate from there.
Yami and Sogen are of utmost importance for this. Yami lets Trial Of Nightmare go toe-to-toe with Uraby, the second strongest non-tribute beater of the format. Witty Phantom surpasses Skull Red Bird, the strongest beatstick without tribute requirement. My 2k defenders also don't mind the additional def (with the exception of Spirit of the Harp who unfortunately falls into Curse of Dragon range under Yami). Similary, Beaver Warrior is safe from any non-tribute beater under Sogen. Gaia at least trades with Dark Magician with it.
My "payoffs" are Two-Pronged attack (going minus two to out a two-tribute monster is surprisingly decent as it re-establishes the advantageous position you previously had just by spamming 2k defenders; the momentum swing from any two-tribute summon is huge), Gaia the Fierce Knight (my best two-tribute guy) and Succubus Knight. I used the last purely because it had incidental synergy with Sogen and my one equip spell. She actually came in clutch in the finals since I established her with the blade and Sogen.
Dark Hole, and Stop Defense are power staples to destroy card advantage from the opponent. Hane-Hane punishes tributes. Swords is pretty nice if you draw any of the monsters not mentioned so far since those are just filler slots that can only secure you the driver's seat with luck.
Mountain is sort of a win more card: It lets Curse of Dragon go over 2k defenders but can snowball negatively if that one falls. Boosting Skull Red Bird is pretty devastating if your deck usually relies on field boosts to withstand it or go over the red menace.
The extra deck is just filler stuff I pulled to trick people into believing I would be stupid enough to run Poly at this stage of the game.
No side deck since even getting to forty cards was enough of a struggle already. Dragon Capture Jar would have been a possible candidate had I pulled it, though.
Things to note: There is no Trap Hole in our format so far, which made tribute summons so much better in theory. Two-pronged attack was, thankfully, largely dismissed by my friends. Don't commit the same mistake in your Prog decks; losing card advantage in favor of board presence isn't that bad if 90% of your cards suck!