index card 3 ring binder 3x5 Lined Cards with Holder and Dividers, 100 Ruled Cards, Blue : Office Products 3 x 5 narrow 3x5 Inch Index Card Binder

It probably just refers to the color you used most often - we don't actually know how they work

Are there more out there that EDHREC hasnt scraped yet

for a detailed step-by-step, see our submission walkthrough

Every other timing rule for casting spells still applies: If the mayhem card is an instant, you can cast it any time you have priority that turn, but if it's a creature you can only cast it at sorcery speed (unless another effect gives it flash)

youll see from there that some special card types may be found in any booster packs, though many are quite hard to come by

Secondly, I love seeing cards Im not familiar with on the opposite side of the table