Riddlekeeper Mill decks in EDH usually suffer from having too many spells and effects that only target one players deck
Remie didn't play a lot of green cards in his main deck or anything, he just realized that as long as a RW deck is already willing to play Bloodstained Mire, Flooded Strand, Windswept Heath, and Wooded Foothills (as Tsapko's straight RW was), it might as well get paid off
Defeat Downy Duo 3 times and it'll unlock Forbidding Fellows as a CPU Tag opponent
Flayer of Loyalties A friend-killer Flayer of Loyalties is a ten-mana 10/10 with annihilator 2, which means that whenever it attacks the defending player has to sacrifice two permanents
With card dividers and a flat white front that allows for clear, concise labeling (my favorite is to put the set icon on the front), its difficult to find something that works better