Twilight Sparkle, the element of magic and personal protege of Princess Celestia, on day stumbles across a a strange book entitled "Death Note." By simply knowing one's face and writing their name in the book, that pony will die within 40 seconds, unless the desired death is specified. Twilight decides to use this power to create a new Equestria with no crime or violence by killing off all of the criminals. Princess Luna decides to personally see to it that the pony nicknamed "Kira" is caught before anymore death can occur.
Set before Twilight becomes a princess
Derpy looking cover art by yours truly.
Crossover with Death Note. Don't like don't read.

Alternate Equestria Girls 2.
In an attempt to return to Canterlot High after receiving Sunset Shimmer's message, Twilight instead ends up in a world dominated by giant humanoid creatures called titans. The remainders humanity have barricaded themselves within three walls: Maria, Rose, and Sina. How will Twilight survive in a world so unlike her own, without her friends to guide her?
Crossover with Attack on Titan/Shingeki no Kyojin. Don't like don't read.