It seems like, outside of the dark brotherhood, most of TES quests tend to be geared towards neutral/good characters ... :/

cool story bro

Even DB quests are not necessarily evil, it's just that you have to perform cold blooded murder (of bad people).
That, or you kill good people out of being deceived by bad people.
That's what makes DB very interesting to me....

There was a deadric shrine quest in Oblivion where you had to extinguish the torches people were carrying so that "underdweller" type people could bash their heads in... That felt rather evil.

But yea, Doing evil for evils sake is rather absent in TES games.

In Oblivion, you kill an entire family. And you're given absolutely no indication that they're bad at the time.

Of course. The dark brotherhood doesn't just kill 'evil' people. The dark brotherhood will kill ANYONE, good or evil, if they are paid enough

Evil quests done by Daedric princes return. I'm sure the brotherhood will have them as well not sure if there will be much more though.

You don't need a quest. Just stalk and kill a random NPC just for kicks. There you go. Evil.

if all else fails, you could just rampage a small settlement lol