Our Lady gets the Credo except on Saturdays (and at votive Masses although some forms of the Rorate indult had a Credo). And she’s either a patron or secondary patron of the places where she was inscribed in the calendar (continental patrons are not that important in the liturgy; I’m talking about the dioceses where the feast was on the calendar as a double of the I or II class).

From comments under a Peter Kwasniewksi post on FB:

According to Innocentius Wapelhorst, the old rule was that DAP days/feasts had the Credo and MUC (or MVC) feasts didn’t.

DAP - credit:
D - Festa Domini, Dominæ, Doctorum, Dominicæ - Feasts of Our Lord, Our Lady, Doctors, and Sundays.
A - Festa Angelorum, Apostolorum -- Feasts of the Angels and of Apostles. Under this, St. Mary Magdalen would be included as "Apostle to the Apostles."
P - Festa Patronum or Titularium Principalium -- Feasts of Patron (of the Church) or Feast of Principal Title.

MUC (or MVC) - non credit:
M - Festa Martyrum - Feasts of Martyrs.
U/V - Festa (non) Virginum - Feasts of Virgins and non-Virgins (widows).
C - Festa Confessorum - Feasts of Confessors.

The octave of the Holy Innocents didn’t get a Credo (being outside of the Octave of Christmas).

Most Old Testament Saints didn’t get a Credo, but the above rule seems to apply much more generally.