Female Trainer/Supporter cards have skyrocketed in both demand and price in recent time, causing the phenomenon within the community known as the Waifu Tax
If you got in on boxes under $190 when those were available in the last few weeks, you may get a chance to flip them for +$40/box at peak hype, and cracking them will be unlikely to cost you much if you need the cards
This includes traditional "gold" cards (cards with more than one color of mana in their mana costs) as well as hybrid cards and split cards (assuming the two costs make use of more than one color of mana)
If an effect counts the number of instant and sorcery cards in your graveyard, There // They're // Their counts once, not three times
If you do, that song gets tucked into the bottom of your deck, so that card isnt gone for good, but you probably wont see it for a while
Of course, we can also start looking forward to what Kaladesh will bring to the format, since spoiler season officially started at PAX West, the site for this years World Championship