Temporal Aperture
2
Artifact
5,T: Shuffle your library, then reveal the top card. Until end of turn, you may play that card as though it were in your hand without paying the casting cost (X is 0).
Not with Temp. Ap. Cateran Emperor is correct for that card. To abuse the top card of your library,
Use Game Preserve, Sylvan Library, and Worldly Tutor. Keep that Reya on top of the deck!
And some random thought :
But 1 copy of Planar Portal should go in any Tinker deck. Why not?