There are quite a few different indulgences in the Raccolta.
On All Souls Day and every day of the octave a plenary indulgence applicable to the dead may be gained on the usual conditions just by visiting a cemetery and praying, even mentally, for the dead. This indulgence is also contained in the 1968 reform.
On All Souls Day itself, and the Sunday immediately following, a plenary indulgence may also be gained for the souls in purgatory every single time you visit a church to pray for the dead on the usual conditions, plus the recitation of six Paters, Aves and Glorias for the Holy Father on each visit. The 1968 reform only grants it once on the day, or with the consent of the Ordinary the Sunday preceding and following plus All Saints Day, and requires the recitation of the Pater and Credo, but not the six Paters Aves and Glorias...