Its been more common for WotC to create new subtypes than main types
Leyline of Sanctity shuts down discard, burn spells, a variety of combos, and some cards you wouldn't expect, like Gifts Ungiven
(Activate only during your upkeep and only once each turn.) You can tap any two untapped white and/or blue creatures you control, including ones you haven't controlled continuously since the beginning of your most recent turn, to pay the cost of Sky Hussar's forecast ability
For each one, Ill tell you why I picked it, and whether I expect to see it in the zone or in the 99
151's pull rates are also fairly forgiving, so you can reasonably expect to get something exciting in a handful of packs, though you must keep in mind that there are no guarantees when buying loose packs, as there's no telling which products they came from