You CAN Play Type I #83: Looking at Legions Part III – Red, White and Blue Creatures
Wizards pointed Type I players to Illusionary Mask when they introduced Morph trigger creatures. Building a deck around Mask, though, requires a bit of work, and you need to Mask out a really good creature to make all that worth it. So far, the standard is set by Phyrexian Dreadnought, and it’s a very tough one.