Welcome to the game and to the forum. 
Guys, neither Dark One’s set nor the beginner guides are available with only the base game.
That said a pet based Conjurer is pretty easy to gear, but you pretty much leave the pets to do all the work for you so might not be your thing. I believe Maya does have some base game pet builds in her collection.
A vitality based Conjurer might also be possible for the base game.
Necromancer isn’t available in the base game, for that mastery you’d need the Ashes of Malmouth expansion.
Commando (Soldier/Demolitionist) can be a fun build as you have plenty of things to throw around from the Demolitionist mastery.