Since we need so many cards to make this work, much of the deck is dedicated to helping find them. That doesn't necessarily make it reliable, but it does make it almost playable.
Shred Memory is probably the best tutor we have. It can transmute into Hearless summoning, a Myr Retriever, or a Chatterstorm, making it the only card that can get any piece of the combo. (It can also tutor up any other 2 drop, but why?)
Commune with the Gods is pretty nifty, since it let's us get either a Myr Retriever or a Heartless Summoning. It can also find Fecundity if that's what you need and you get lucky. At first glance, the fact that it puts the extra cards into our graveyard seems helpful with gravestorm, but it is not.
Fecundity Is really just for finding Bitter Ordeal or Chatterstorm. You really need to have Heartless Summoning and the Myr Retrievers doing their thing for Fecundity to be useful, but once you do it will draw your entire deck. It's pretty useless outside of that. But I've always wanted to put it in a modern deck and this was the best I could come up with, so it stays.
Infernal Tutor is basically just a 5th copy of Myr Retriever.
Dark Confidant and Nurturing Peatland are just there to draw extra cards in exchange for some life.
