Most of the chord progressions can be classified into three broad categories: prolongational, sequential and cadential.
A prolongational progression can be either a prolongation of harmony or a prolongation of harmonic function. Prolongations of harmony will be explained in the next chapter. Prolongations of harmonic function will be explained in chapter Prolongations of harmonic function, after explaining harmonic functions.
A sequential progression is also called a harmonic sequence. Sequential progressions will be explained in chapter Harmonic sequences.
Cadential progressions were already explained in the chapters about cadences.