I watch mostly dark or psychological thriller anime recently and I gotta say Another is pretty awesome, from the first list posted i've seen Gantz (omg i'm obsessed with Gantz, trying to find a full english translation of Gantz/Minus in one place after reading the manga, watching the anime and film.. Yeah, obsessed. ) and Black Butler.
Gantz just seems like mindless violence tbh, I really like the plot but the anime is just... awful at explaining /anything/, the ending is so... Unsatisfactory.
Black Butler is a feels trip, and one of the few anime I prefer the anime ending to the manga ending.
Is this your sort of genre?