You will not see many but they do tend to prove an annoyance. Arachnids are easiest to deal with from a distance with broadhead arrows. There are several varieties of humanoids. You can expect to encounter Servants, Civilians, Guards, Thieves, Mechanists, ape beasts, tree beasts, and Hammers. Humanoids will comprise the majority of enemies that you will encounter, so know how to defeat them well, as you will have to on a regular basis.
Most humanoids are highly susceptible to a blackjack strike on the back of the head.
The only unfortunate thing is that this does not work on tree beasts, ape beasts, or all guards. Because of this you will need to pay close attention to an enemy before blackjacking them. If they cannot be knocked out like that, they will turn on you and strike. The only real variations that you need to watch out for are the occasional Guard Archer or Mechanist Crossbowman. Other than that most of these enemies that you encounter will be rather standard, and are easily knocked out via a blackjack strike.