The Eldrazi are a fascinating type of Creature that are all covered in tentacles, are highly destructive, and for some players, responsible for one of the worst periods in Modern of all time thanks to the Eldrazi Winter
One theme deck gives you 60 cards the exact same as the theme deck the code came from
You want to look at Rally the Ranks, Cathars' Crusade, and Wedding Announcement
They can be explained as follows: Fire and Fighting Energy appeared both in the 2-player starter deck as well as one theme deck each, and thus appear the least frequently in the booster packs
With more lands coming into play, cards like Tireless Tracker, Avenger of Zendikar, Toph, Earthbending Master, and the like become more powerful