http://gatherer.wizards.com/Pages/Search/Default.aspx?action=advanced&cmc=+%3E=%5B6%5D&type=+%5B%22Creature%22%5D&rarity=+%5BR%5D&set=|%5B%22Kaladesh%22%5D|%5B%22Amonkhet%22%5D|%5B%22Aether%20Revolt%22%5D

This is a search of all rare creatures with converted mana cost 6 or more from the last three blocks, interestly none of them require you to untap with them to do anything unless they have either some form of recursion or some form of cost reduction.

Now stuff like vehicles, embalm and possibly eternalize might have mined in that design space, but I find interesting that the only cards that fit that description in the last three sets where mythics, note that MINOR SPOILER FROM IXALAN there are at least 1-2 rares from ixalan that fit this description, plus one with a somewhat minor etb effect(gaining 5 life ).

Why would this be a side effect of planeswalker packs and welcome decks? It just seems like general power creep.


Thanks for the caps warning.

Because a lot of these creatures looked splashy enough to appear on the front of intro packs.

Interesting thought, but I think you're stretching here. The point of expensive rares has always been to be splashy, going all the way back to Shivan Dragon in Alpha.