So the second set, Rise of the Floodborn, didnt seek to reinvent the wheel, with perhaps the biggest addition being the damage reducing Resist keyword
Even the impulse draw mechanic (exile the top card, you may play it this turn) is a consistent form of card advantage, because you can always play those cards as lands
Numa, Joraga Chieftain adds the ability to pump her up so she can deal more damage and make even more Saprolings
As for opening these serialized cards, you can only get them in collector boosters of the appropriate MTG set
While this gives the player more options, it also means you dont have to reveal what you found, which is a big deal at more competitive tables
Natural Order Not much can beat Natural Order in terms of straight-up value