So you get different loot from which kinda character you want to be?
You get different loot from what you fight.
There'll be specific monster drops, like those imps that attacked you can drop "imp gall," and mudcrabs will drop "crab meat." Humanoids will often drop a little gold, and sometimes potions, plus you can loot their gear. What appears is generated randomly, but it'll always be from a list of certain things.
Containers are usually random too, but over time you'll figure out the kinds of things to be found in crates, barrels, chests, and sacks.
Some of the dungeons are involved in a quest, like "go to [
specific location] and get [
specific item] for me," and others have interesting storylines or items to discover, but most are just for exploration and looting.