Since we are St. Mary's, here is a list of some of the Marian Feast Days.
The principal feasts are in bold.
Marian feasts originate ultimately or primarily by ecclesial decision. The Church decides whether they should be local, regional or universal, and what degree of solemnity should be attributed to them (solemnity, feast, memorial) depending on the importance of the theme celebrated.
1 The Blessed Virgin Mary, Mother of God - The Solemnity of Mary - the oldest Marian feast of the Church of Rome. It commemorates Mary's vocation to be the mother of Jesus Christ. Mary as the Mother of God was first defined at the Council of Ephesus in 431 A.D., but the concept is much older. Holy Day of Obligation
5 Our Lady of Abundance or Prosperity (Cursi, Italy)
8 Our Lady of Prompt Succor
13 Our Lady of Victory (Prague, Czechoslovakia).
14 Our Lady of the Word (Montserrat, Spain)
16 Our Lady, Refuge of sinners (Spain)
17 Our Lady of Peace, Rome (1483)
21 Our Lady of Consolation (Rome)
23 Our Lady's Espousals to St. Joseph
24 Our Lady of Tears.
27 Our Lady of Life (Provence, France).
28 Our Lady of Good Succor (Rouen, France).
2 Our Lady of Purification and the Presentation of Our Lord - commemorates the offering made by Mary and Joseph of the infant Jesus in the temple, forty days after his birth. The story is told in Luke 1:22-39.
11 Our Lady of Lourdes
25 Our Lady of Victory (Constantinople).
Our Lady of Great Power (Quebec, Canada)
27 Our Lady of Light (Lisbon, Portugal and Palermo, Italy).
2 Our Lady of Apparitions (Madrid, Spain)
5 Our Lady of Good Help (Montreal Canada)
8 Our Lady of Virtues (Lisbon, Portugal)
10 Our Lady of the Vine (Tuscany, Italy)
11 Our Lady of the Forests (Porto, Portugal and Britain)
12 Our Lady of Miracles (St. Maur des Fosses, France)
23 Our Lady of Victories
25 Annunciation by Archangel Gabriel - commemorates the angel Gabriel coming to Mary to announce that she will bear the Son of God and that God's divine nature will be united with human nature in the person of Jesus Christ. He also tells her that her cousin Elizabeth will bear a late-in-life baby who turns out to be John the Baptist. Luke 1:26-38 relates the story of the Annunciation. (may be either moved to the day before Palm Sunday should this date be on Holy Week; or to the Monday after the second Sunday of Easter if this date falls on either Friday or Saturday of Holy Week or during Easter Week.
27 Apparition of Our Lord to Our Lady, as soon as He was risen from the dead.
31 Our Lady of the Holy Cross (Jerusalem)
1 Our Lady of Tears (Sicily).
2 Our Lady of Light (Zeitoun, Egypt)
Our Lady of the Highest Grace (Higuey, Dominican Republic)
3 Apparition of Our Lord to Our Lady & the Apostles in the upper room
4 Our Lady of Grace (Normandy, France)
5 Our Lady of Divine Providence (Cussanio, Italy)
6 Our Lady of the Conception (Flanders)
21 Institution of the Confraternity of the Immaculate Conception (Toledo, Spain)
26 Mary, Mother of Good Counsel
29 Our Lady of Faith (Amiens, France)
1 Queen of Heaven
12 Our Lady of Power (Aubervillers, France)
13 Our Lady of Fatima
Dedication of Our Lady of Martyrs (Rome)
Our Lady of the Blessed Sacrament
17 Our Lady of Tears (Spoletto, Italy).
21 Our Lady of Sweat (Salerno, Italy).
24 Mary Help of Christians
31 Mary, Mediatrix of all Graces - Our Lady of Grace
Feast of the Visitation of the Blessed Virgin Mary to Elizabeth
Our Lady of All Nations
9 Our Lady, Virgin Mother of Grace
13 Second Apparition of Our Lady of Fatima
17 Our Lady of the Forest (Britanny, France)
20 Our Lady of Consolation (Luxemburg)
25 Divine Motherhood of Our Lady
25 Our Lady Queen of Peace
26 La Conquistadora, Queen of Conquering Peace
27 Our Lady of Perpetual Help - Our Lady of Perpetual Succor
28 Institution of the Angelus of Our Lady (Europe)
1 The Immaculate Heart of Mary
2 Our Lady of Light
Visitation of the Blessed Virgin
4 Our Lady of Miracles (Avignon, France)
9 Our Lady of the Atonement (Graymoor, New York)
13 Third Apparition of Our Lady of Fatima
16 Our Lady of Mount Carmel - Feast of the Brown Scapular
17 The Humility of the Blessed Virgin Mary
22 Our Lady of Safety or of Safe Hiding (Overloon, Holland)
26 Our Lady of Faith (Cauchy)
27 Our Lady of Faith (Gravelines)
28 Victory over the Turks by the Knights of Rhodes in 1480 through Our Lady’s intercession
29 Our Lady of Deliverance (Madrid, Spain)
31 Our Lady of the Slain (Lorban, Portugal)
2 Our Lady of Angels (Assisi, Italy)
5 Dedication of the Basilica of Saint Mary Major
10 Institution of the Order of Our Lady of Mercy (Barcelona, Spain)
11 Our Lady of the Way (St. Charles, Missouri)
13 The Dormition of the Blessed Virgin Mary
13 Our Lady, Refuge of Sinners
13 Fourth Apparition of Our Lady of Fatima
15 Solemnity of the Assumption into Heaven - Our Lady of the Assumption - celebrates Mary's entrance into heaven, body and soul. Because of her perpetually sinless state, Mary is the first among the faithful to be fully redeemed. Catholics believe that because of Mary's close relationship to her son, Jesus, she shares through privileged anticipation in the grace of the resurrection of the dead. Mary does not have to endure the suspension of eternal life until the resurrection of the dead. The Assumption of Mary was declared a dogma of faith, and so to be believed by faithful Catholics, by Pope Pius XII on Nov. 1, 1950.
22 Queenship of Mary - Our Lady, Queen of Heaven
29 Our Lady of Good Health
15 Assumption of the Blessed Virgin Mary into Heaven
16 Feast of Our Lady of the Divine Will
18 Coronation of Our Lady
22 Queenship of Mary - Octave of the Assumption
23 Feast of the Immaculate Heart of Mary (traditional)
27 7 Joys of the Blessed Virgin Mary
3 Our Lady of the Divine Shepherd (France)
4 Our Lady of Haut, Restores Life to Young Woman (Belgium)
5 Our Lady of the Woods (Galloro)
6 Our Lady of the Fountain (Valenciennes, France)
8 Nativity of the Blessed Virgin Mary - St. Mary's Birthday
Our Lady of Charity
12 The Most Holy Name of the Blessed Virgin Mary
13 Fifth Apparition of Our Lady of Fatima
15 Our Lady of Sorrows
16 Our Lady of Good News (Sicily)
19 Our Lady of La Salette (France)
22 Our Lady, Queen of Peace
The Giving of the Name of Mary to Our Lady by St. Ann, Her mother
24 Our Lady of Walsingham
Our Lady of Ransom(Spain)
Our Lady of Mercy
27 Our Lady of Happy Assembly (Le Laus, France)
1 The Holy Protection of the Mother of God
2 Our Lady of the Assumption (Naples, Italy)
6 Our Lady of All Help.
7 Our Lady of the Most Holy Rosary
8 Our Lady of Remedy
11 Feast of the Divine Maternity of Our Lady - The Motherhood of Mary
12 Our Lady of Faith (Liege, Belgium)
13 Sixth Apparition of Our Lady of Fatima
16 The Feast of Purity of the Blessed Virgin Mary
23 Our Lady of Consolation (Near Honfleur, France)
26 Our Lady of Victory (Near Senlis, France)
16 Our Lady of Mercy
21 Presentation of Mary
27 Our Lady of The Miraculous Medal
3 Our Lady of Victory (Paris, France)
8 Immaculate Conception - Although many mistakenly believe it to refer to Jesus, the feast of the Immaculate Conception on Dec. 8 celebrates Mary's being conceived free from all sin, particularly the original sin that all descendants of Adam and Eve inherit as a consequence of the pair's fall from grace in the Garden of Eden that is recounted in Genesis 3. Mary's preservation from original sin was proclaimed by Pope Pius IX on Dec. 8, 1854. Jesus' freedom from sin was never in question.
12 Our Lady of Guadalupe - Patroness of the Americas, here in Texas it’s a big deal(Mexico)
15 Our Lady of the Armed Forces
16 Our Lady of Good or Happy Deliverance, brought from Madrid, Spain to St. Augustine, Florida
18 Expectation of the Blessed Virgin Mary
23 The Espousals of the Virgin Mary
24 Chaste Nuptials of Our Lady and St. Joseph
25 The Birth of Jesus. (Delivery of Mary)
The 7 Sorrows of Mary - 5th Friday of Lent (between March 13 and April 16)
Our Lady, Queen of the Apostles - 6th Saturday of Easter (between May 2 and June 5)
The Immaculate Heart of Mary - Saturday after Pentecost (between May 30 and July 3)
Our Lady, Health of the Sick - Saturday between August 24 and 30
Our Lady of Consolation, Saturday between August 29 and September 4
Mary, Mother of Divine Providence - Saturday between November 14 and 20
The Seven dolors of Our Lady - Traditionally celebrated on Passion Sunday
Our Lady of the Sacred Heart - Last Saturday of the Month of May
Mother of Mercy - Saturday before the fourth Sunday of July.
Catholic Doors has an even more complete list.