Six mana may be a lot, but artifact decks often have ways to create a lot of it pretty easily
While doing Unhinged , I was aware that I wanted a number of throwbacks to Unglued
Tyvar the Bellicose This legendary Golgari Elf Warrior hails from the despised March of the Machine: The Aftermath set, which sees a desparked Tyvar turn into an excellent mana dork lord, especially for Elves
While there are green tricks (Gaeas Might, and Colossal Growth) I saw them a lot less, and the beef of green creatures in the set generally makes them less necessary
Deathtouch is a very helpful keyword to have on a creature in the early game, and the ability to look at the top of your library and play lands and spells (with mana value 4 or greater) from the top of your library is pretty sweet
Paired with cards like Foundry Inspector, Paradoxical Outcome, and a bunch of small, cheap artifacts, and you got yourself a stew