Deadman Wonderland
Ganta is the only survivor after a mysterious man in red slaughters a classroom full of teenagers. He's framed for the carnage, sentenced to die, and locked away in the most twisted prison ever built: Deadman Wonderland. And then it gets worse.
Btooom!
Sakamoto, an unemployed young man, is one of the world's top players of an online fighting game called Btooom! One day, he wakes up on what appears to be a tropical island, although he doesn't remember how or why he got there.
Gargantia on the Verdurous Planet
While fighting an intense inter-galactic war, a mecha pilot is accidentally warped into a space-time neither he nor his computer recognize. After waking up from a long-time hibernation, he finds himself trapped on a planet, with human residents talking in an unknown form of language, using inferior technologies, and - most shocking to him - naturally breathable air.
7SEEDS
Shy Natsu awakens as part of a group chosen to ensure the survival of humanity. Together, they have to survive on a changed Earth.