Captain Nagisus
Jake the Dog!
Every single dwarven ruin can give tremendous amounts of sellable loot. I actually think regular Dwarven ruins like Mzulft are better for money, because there are more pieces of dwarven scrap. Dwarven scrap can be used to make ingots to make armour, so you can make a lot of profit from those ruins. Blackreach does, however, have a bunch of giants, centurions and a dragon. If you want to make money and you can cope with a centurion, just go around obliterating animunculi.