Contrapuntalism
When we look at patterns in music, one of the necessary questions we must ask ourselves is: What effect does this have on the piece? While many people value chords and harmony in music, contrapuntalism does not necessarily rely on that. Instead it just flows with the juxtaposed melodies, with chords sounding where notes incidentally happen to be in the right place. The contrupantalism often gives the piece the ornamented yet somewhat theatrical feel that characterizes many Baroque pieces. Examples of forms that use contrapuntalism are the canon and fugue.
Ornamentation
While not officially a pattern in music, ornamentation was the defining characteristic of Baroque music. Different from other ornaments in music, these ornaments were not completely necessary in the piece and often happened on the beats of the piece, which contributed to the grand theatricality that characterized many Baroque pieces.
Table of Ornaments, written by JS Bach
http://upload.wikimedia.org/wikipedia/commons/7/78/Tableofornaments750.jpg
musematics 
