Typology, as described by Wikipedia, means the classification of things according to their characteristics.
There are three types of Sacraments:
A. Sacraments of Initiation - the Sacraments that bring people into the Church and unite them with Christ (Baptism, Confirmation, Eucharist)
B. Sacraments of Healing - the Sacraments that provide healing to body and soul (Anointing of the Sick, Confession/Reconciliation)
C. Sacraments of Vocation - the Sacraments that institute a God-given mission to man on earth (Matrimony, Holy Orders)