That theory is correcthumidity changes cause expansion and contraction of the fibers that make up the cardboard side of the card, causing it to swell or shrink based on how much moisture is added or removed
If you want some inspiration for meta decks, tournament successful lists, or wanna see different strategies, look at the completed results from a recent Late Night Event here: You can import a deck from one of those events by copying it to your clipboard and pasting it right into PTCG Live
Market corrections typically last 6-18 months before stabilization, based on historical collectibles patterns
There is 1 foil in every pack
Drannith Magistrate Drannith Magistrate does little outside of Commander, but boy is it fantastic there
Theres also a secret deck which features 3 Mega cards, and even one with a variant, gold Mega Charizard Y ex