Buried toward the back of the Preface section of the Roman Missal, numbers 72 through 77 of the Order of Mass, are six prefaces which are labelled “Common.” Each of the six is accompanied by a rubric which states:
The following Preface is said in Masses that have no proper Preface, and for which a Preface related to a specific liturgical time is not indicated.
I would interpret this as any Ordinary weekday for which there is not an assigned saint–apostle, martyr, or such. Or any day on which an optional memorial is observed for which the faith community has taken the option of not celebrating or observing.
The English translation of the Roman Missal Second Edition labeled these “for General Use,” and includes what appears to be an original composition as the seventh of this section. Over the next week, I’ll offer a brief write-up of each of these. We’ll see where it leads. Perhaps if you are a regular celebrant of a daily Mass, priest or lay person, you may recognize one or more, and possibly have a favorite.