A few of these may already be in here, but
Log Horizon 1 & 2 - A fun isekai adventure. Think SAO but they spent more time on the worldbuilding.
Overlord - Imagine SAO, except the main character is an evil skeleton.
No Game No Life - Two siblings use genius plans to take over a world of games.
Mondaiji-tachi ga Isekai kara Kuru Sou Desu yo - A couple of teenagers with superpowers are warped into a world of games.
Hellsing Ultimate - A gory funfest of werewolves and vampires. Did you know Alucard backwards spells Dracula?
Darker than Black - Chinese Electric Batman works for the mafia. Season 2 doesn't exist.
Katanagatari - He says he's learned 'Kyotōryū,' a school of sword martial arts, but he never actually uses a sword.
Medaka Box - Welcome to Sandbox Academy, where the student council president's job is to move the school. Literally, sometimes.
Star Driver - Thanks Takuto-kun, very cool. The main character is literally called 'The Galactic Pretty-Boy.' A mech-of-the week anime.
The Legend of the Legendary Heroes - Ryner Lute carries this thing called the Alpha Stigma. Trifle with it at your own peril.