While having to ban cards in Standard is bad, hyping up a new card type and having it fall flat and go unplayed is (perhaps) just as bad, so Wizards is incentivized to take more risks to make sure new card types see play
I'm a bit disappointed that they didn't do it here though
Each Mystery Booster 2 pack will have two commons and uncommons of each color from these lists, one common or uncommon multicolor, colorless or land card, and one rare or mythic picked from any of them.
For those looking for smaller, more portable options, empty Prerelease Pack boxes offer a compact solution for transporting a single 60-card deck or a small selection of Magic: The Gathering tokens and emblems
If you are looking for custom Magic the Gathering sleeves, deck boxes and custom Magic the Gathering mats, click on this link