.hack//Sign, Log Horizon Recommendations
Both are fantasy elements and both stories are simulated inside of video game worlds.
Both Protagonists undergo great changes during the course of the story, and both series explore human nature and life.
The main character from SIGN is a Wavermaster. In Log Horizon's case a Mage/magic user. Both series deal with players trapped in an MMORPG except Tsukasa is the only one who can't log out. They must find a way to escape this death game.
Both involve strange events surrounding and online game. In Sign it's only one player who can't log out but in this one it's a ton of players
Yet another trapped in the video game style of story. Log Horizon has a lot of serious undertones like .hack//Sign, but it's also a very fun series and has excellent characters.
Both of these series involve people who are locked inside of an MMO game and cannot leave. Though the situations are similar, the stories differ in that in the case of .hack//SIGN, only one player is trapped in the game and the story revolves around the people in the game who try to help and how they change as a result of their interactions with Tsukasa. SIGN is good, but it's very slow to develop. If you prefer a show with a faster pace, Log Horizon may be the better choice. Instead of only one character, everyone is trapped inside of
Both are about a bunch of people getting stuck in games, and the main character are to themselves.
They also have some type of special ability.