While Craft has some additive abilities that can cause confusion, and Descend or Descended really feels like three different keywords mashed into one, the new MTG Discover mechanic is definitely the most complex of the three at least, without additional context
For example, new Voidvelgrs like Apocalypse were introduced to the game but Zwijo didn't get a new deck to show them off, and heck, with the exception of Yuna's first deck NONE of them run Fusion at all
Almost too powerful if you ask me
Emrakul, the World Anew You have to be a very ramp-centric strategy to make Emrakul, the World Anew a functional part of your deck, but its a glorious top-end card
I didnt play much of this back in the day, but I heard you can get valuable artifact armour sets for the Fighter, White Mage, and Beast Master here
Seven Dwarves and Nazgl have restrictions on how many you can play, but you can include up to that many of each in their EDH decks