I keep up with a lot of media from light novels, books, manga, and anime. Recently, going back through time to search out old animes that I missed the first time around. Just finished Blue Gender and I recommend it if you want to see something similar to Attack on Titans.
Light Novels
Player's get trapped in a game world. Overtime, they realize the game world has actually become a REAL fantasy world. A lot of interesting themes are explored here.
The story is about a martial artist, think Avatar the Last Airbender or any old chinese movie, who is nearly killed. He is saved by a bunch of wizards and taken through a portal to their land. It is a classic western mythology vs eastern mythology. I enjoyed it because it was always fascinating to see him interact with the world and surprise everyone. He killed giants, nearly 20 feet tall, which can topple hundreds of men all by himself with his bare fists, something unheard of in western lore. He is also something of a tragic character. The novels are in korean so I was not able to finish them all.
The same genre as Dark Mage. A man who trained with beautiful women who eventually becomes very feminine in appearance. He gets transported into a different dimension(european fantasy land) where his martial abilities are unbelievable. Compared to dwarves, men, and elves who have to swing swords to kill each other. He can block and break swords with his fists. Flick drops of water as strong as bullets with his fingers. They also compared his speed to a wizard who has casted haste to himself, shocking people who watched him cause he used no incantations, they also don't sense any magic, making him a very mysterious and powerful entity in this world.
Books
A story about a dragon hatched from a egg and about 1000 years of his life. He is hunted by dwarves. Feared by humans. Grows large and huge. Very powerful. But for the first few hundred years of his life he is but a small dragon and can be killed by an angry mob of men and small wild animals. It's a very nice tale of him growing up and learning to live and survive. Also learns a few animal languages that lets him speak to birds and other creatures of nature. By growling and learning their body expressions. Something men cannot do. I always hate books with people riding large dragons(practically all fantasy). Finally a book where dragons eat people who attempt to do stupid things like ride them.
If you seen the movie the book is more dramatic in the ending.
The life of a boy who eventually caught the eye of an assassin. He is raised as an assassin from a very young age. His life is very interesting. Full of tricks and violence. I don't recommend the rest of the series for how dark it gets. First book is good though. Better than Assassin Creed video games that used to be good, but now is just being milked for money.
Manga
A portal gets open in the modern world to a fantasy world. Mythical creatures pour in to invade and get annihilated by machine guns. It's modern vs fantasy. The fantasy world people think guns are magic, helicopters are chariots, and the people right now in modern Japan possess powers stronger than Gods. It's does this nice fear play on both sides with Japan trying to decide whether they want to invade the Fantasy land. Like America did to the Indians.
Mech manga. World is destroyed by aliens. Main character is killed in the first few seconds. He wakes up and repeats the last 24 hrs of his life. He remembers everything. Trying to survive a little longer every time. Turning from a newbie to a monster that breathes and spews blood. Incredible difference. He writes his deaths on his hand to remember how many times he has died. Trying to survive impossible odds. Try 1,000,000,000 vs just him. I exaggerate, but the sense of impending death is overwhelming. Series can go anywhere, but already all the signs of being an epic story is there.
Anime
If you do not know this anime you have not watched anime. Greatest Space Opera Anime of All Time. Not disputed. Everyone agrees. 110 episodes. Only one flashback. Depth is very deep. Strategy is compelling. No one is stupid. You watch Death Note. You watched Code Geass. Everyone is Lelouch. Everyone is L or Light. It is about smart people against smart ppl trying to get the edge on each other in combat. Some ppl are better than others, but the result is amazing. Was made in 1980s or before so don't expect good graphics. Expect phenomenal story.