darker than black is also like ergo proxy but i don't think is considered sci.fic
- serial Experiments Lain
They both have an intelligent plot and well-portrayed characters that have flaws and act like actual people.
- Texhnolyze
Both anime share a similar dark feel, though Texhnolyze is admittedly a bit more claustraphobic. Both have excellent music, interesting characters, and "what the heck is really going on?" storylines.
- pale cocoon
the main character's longing to discover what lies beyond the city walls and find out what has happened outside of their boring, formatted refuge for model citizens.
- ghost in shell
Both are cyber-punk masterpieces set in a distant future. The heroines have a unique perspective of the technologically-overwhelmed worlds they live in and try to cope with their jobs
- elfen lied (not sci fic but is amazing)
There is an undertone of experimentation on people and having them become demons in Elfen Lied and Ergo Proxy. The two main characters in the series, Lucy and Vincent Law respectively, have the same sort of out look on life and are trying to find a change in their own lives
- Kaiba
Both are relatively intelligent series that are initially confusing, but makes more sense after a rewatch.
- BLAME (ova)
are dark and unusual sci-fi titles. Both take place in a post apocalyptic scenario set in the future. A brooding atmosphere serves as the backdrop for the interaction between humans and thinking machines
- betterman
The mystery of Betterman simply eats at you to figure out the meaning of everything. You are drawn in by the moments of overwhelming paranoia, the lingering notions why has algernon come into existance, why and how does Lamia transform
- Noein
The series have many differences, but both have a kind of "otherworldly" feel to them, and hold the possibility of becoming a possible future
- Claymore (not sci fic but also REALLY good)
Real and Clair both share simalar art concepts.
Both animes seem to have a smoky feel due to the enviroment. Both are enjoyable to watch while working out. Both are also excellent manga. Very good for their action and mystry.
hope it helps u :)