Sometimes the feast day is the memorial of the date when the person died, or was reborn into Heaven. Sometimes it is another important date in the life of the person, such as the feast day of John Neumann which is the anniversary of the date he converted to Catholicism. Other times it is a date picked, more or less, in random.
Pope Benedict I is not a saint and has no feast day.
Saint Maria Goretti's Feast Day is July 6th.
The feast day of saint Mark is April 25.
Saint Christopher's feast day is July 25th.
Saint Laura's Feast Day is October the 19th.
Saint Helena's feast day is August 18.
July 24 is the feast day of Saint Charbel.
August 11 is the feast day of Saint Philomena.
November 22 is the feast day of Saint Cecilia.
The 23rd of April is the feast day of Saint George.
The feast day of Saint Apollonia of Alexandria is on February 9.
The feast day of Saint Anastasia of Sirmium is on December 25.