Engines would be:

Blood frenzy
Tome of knowledge
I’ll gotten gains
Bazaar
Wraith of the forest
Wizents staff
Survivalist
Elicit information

There are not that many engines in shadow era. Historically they were usually the preeminent or strongest form of card draw. Upon shadow eras release options were limited both in forms of good...

So a draw engine from my understanding tends to refer to either an item (mostly artifacts with some exceptions.. example wizent staff is a weapon but I would consider it an engine) or an attachment. ...

I would categorize this as a list of cards that provide card advantage There are several distinctions to be made...

Cantrip If a card has the effect of adding one and only one card to your hand...