St Joseph is a very special, and often overlooked Saint. Adopted father of Jesus and husband to Mary, Joseph was the protector of the Holy Family. Joseph showed mercy to Mary when he didn't understand how she came to be with child. He ensured that Jesus had a safe place to be born, and that Mary and Jesus had a safe place to live their lives.
"Angel" means messenger, but the Archangel Gabriel seems to be God's special messenger, particularly of messages concerning Christ. In the Gospel of Luke, Gabriel announces the conception of John the Baptist to his father, Zacharias. Gabriel also announces to Mary God's wish for her to be the bearer of His son. In the Old Testament, Gabriel interprets Daniel's dreams and foretells the coming of the Christ.
Our Lady of Guadalupe is an apparition of the Blessed Virgin to Juan Diego on a hill outside of modern day Mexico City. When she appeared to Juan Diego, he went to the archbishop to share his experience. The archbishop asked for a sign, and Our Lady obliged by directing Juan Diego to collect roses in his cloak.
St Thérèse is the patroness of CatholicTV, and (among other things) she's also a patron of missionaries.
Prayer for March 2016: Families in Difficulty and Persecuted Christians