Yu-gi-oh, as in all adaptions, Fullmetal Alchemist Brotherhood, Future Diary, Fairy Tail, Bleach, Death Note, Berserk, Assassination Classroom, Kill La Kill, Attack On Titan, Tokyo Ghoul, Fate/Stay Night all adaptions, Pokemon, Soul Eater, One Piece, Akame Ga Kill, Dusk Maiden of Amnesia, Steins; Gate, Sword Art Online, Strike The Blood, Deadman Wonderland, Sankarea, and tons more but those are the ones I like and come to mind. Also a hint of having a lot of free time.