Notes & Combos
Pretty easy climb up to D5, but D1 will be a challenge. The addition of Myutant Mutant has increased the power of this deck exponentially, playing it in previous seasons felt terrible, and now it isn't super painful to climb with, though not as easy as meta decks.
Shifter is mandatory in my opinion, this deck isn't super great, so the ability to essentially skip your opponent's turn is always great. I am not running handtraps that conflict with shifters (Anything that NEEDS to go to grave) like Maxx C, Veiler, Ogre, etc. Shifter over Maxx C because Runick doesn't care about Maxx C. There Can Be Only One is nearly useless against Runick and Branded but is an insta-win against most tier 2 strategies and it's stolen quite a few wins. Macro is our main win-con against Runick, completely kills their engine, also very good against Branded. As much as I really don't like running Colossus he's just too good to not run. Don't run extrav, you need at least 2 Synthesis in your extra or you probably just lose.
Extra deck isn't very important aside from the Myutant cards and Colossus, though I highly highly recommend running the Numeron Dragon package (Numeron Dragon + Draglubion + A dragon number monster, I'm running Hope Harb in that slot), it has stolen so many wins. Anima is cool, has decent utility. Lancer can be good but his negate is mandatory, he's mostly for Zeus, but has other utility. I have never summoned Cross Sheep.
Top Secret Packs used

Resource generation. Here's a hypothetical to help visualize it: Let's say you have M-05 and nothing else. M-05 searches ST, banish ST to make Beast. You've spent used 1 card to make 1 card, and have gone card neutral. If you then pass to your opponent and your opponent activates a spell you want to negate, you then banish a card to negate that card, and have gone again card neutral. However, with Keystone, if you search ST with M-05, then banish Keystone for Beast, Keystone adds itself back to hand in the end phase, and now you've spent a card to make a card, and have gone +1. If you then pass to your opponent and negate a spell banishing Keystone, it will add itself back to hand in the end phase, and you have spent no cards to negate one of your opponent's cards, going +1 again. So the difference between not having Keystone and having Keystone is a +2 card advantage difference.