Spells that used and manipulated time and included time travel.
Many spells use some level of Chronomancy, such as Slow or Haste -- but actual chronomancy is a lost art. The master of the magic was Jeriah Chronos who worked with Captain Meklan. Their chronomancy spells have been lost to the ages, but there has been rumors that some in the Arcane Order have been seeking a book that hides knowledge of this school.
I really do try to make most of this original, but since Forgotten Realms is an integral part of the world I can't help if anything is used without formal permission, but is still "fair use" as I am just using this for my private games.