Perfect Fit

Enchantment

Whenever this would be shuffled into your Draw Pile, place it on the top instead.

Perfect Fit rises to the top of the draw pile whenever the discard pile reshuffles into it.

First cycle: the initial shuffle at combat start does not count, so the card sits wherever it lands until you have gone through the deck once.
After that: every later shuffle of the discard pile into the draw pile pulls the card back to the top, so it is the first card you draw each new cycle.
Field of Man-Sized Holes: the only source, an event in the Hive that appears only when you own an enchantable card.
Entering your hole: enchants one card.
Resisting: removes two cards and adds the Normality curse instead.

Comes from

1 eventField of Man-Sized Holes

Where it comes from

Best target: a card you want in every hand, in a deck that reshuffles often.
Reboot: shuffles everything and draws 4, so the enchanted card is guaranteed among them.
Suppress and Mind Blast: Innate, so they cover the first cycle themselves and Perfect Fit covers the rest.
Comet and Bludgeon: the big hits you want back the moment the deck turns over.
Exhaust cards: such as Backstab waste it, since they never reach the shuffle.