Duration draw is a collective term for abilities that increase the number of cards you have in hand at the start of your turn. Most of the effects that provide duration draw are Duration cards—hence the name—but there exist Events, a Boon, an Artifact, and a Project with duration-draw effects as well, as well as Reaction cards that add themselves to your hand at the start of your turn.
Duration draw is valuable in engine decks because it increases the probability that you will be able to line up key engine components to start your turn; the effect is therefore similar to guaranteeing a non-terminal draw card in a normal-sized hand. The power of duration-draw cards is mitigated by the fact that as Duration cards, they remain in play for multiple turns, and can therefore be played less frequently than comparable non-Duration cards. Moreover, the benefit duration-draw cards provide is delayed; most of them provide little or no value on the turn you play them. One reason Wharf and Gear are considered very powerful cards is because they can provide both terminal draw when you play them and duration draw the next turn.
Duration-draw cards often provide defense against handsize attacks, since they can allow you to re-draw to a full-size hand after being hit by an Attack like Militia. However, this is not true of the Events or Artifact with similar effects, because they increase your handsize before you're hit by the Attacks.
 List of sources of duration draw
- Faithful Hound, Haven
- Cargo Ship, Enchantress, Gear, Ghost Town
- Caravan, Flag Bearer (via Flag), Horse Traders, Research
- Archive, Cobbler, Crypt, Den of Sin, Haunted Woods, Tactician, Wharf
Prince and Ghost can provide duration draw if they set aside an action that provides at least +1 Card. Dungeon and Guide don't increase your handsize at the start of your turn, but they do sift your hand.
Summon, like Prince, can provide duration draw if it sets aside a card that draws.