Catholic Mass Hymns
This is Catholic Mass Hymns used during Liturgical Celebration of the Holy Mass. These Hymns are classifies under:

Entrance Hymns
Penitential Hymns
Offertory Hymns
Communion Hymns
Post Communion Hymns and
Dismissal Hymns

 Entrance Hymns
These are Hymns sung when the priest is in procession to enter the Church to begin the Holy Mass.
Penitential Hymns
These are Hymns used during Penitential Rite during Mass. Penitential Rite is the act of expiation done before we enter deep into the Holy Mass. It is used to cleanse us and make us worthy to be in the presence of God and ask Him for our needs, or even offer Him our praise.
Offertory Hymns
These are Hymns used during Offertory. Offertory is a period during Mass when we offer our material belongings to God as sacrifice of Thanksgiving for His wonderful deeds in our lives.
Communion Hymns
These are Hymns we use during the period of reception of Holy Communion. There most and always very Solemn.
Post Communion Hymns
These are Hymns we use after the reception of the Holy Communion to welcome the True God whom we received in Bread and Wine.
Dismissal Hymns
These are Hymns we sing when the priest has dismissed from the Mass and is in procession into the Sacristy with the Altar servers. These Hymns are often  Hymns of Thanksgiving to God for granting us the Grace to be in the Mass for that day.

All these Classes of Hymns are being made available here by Catholic Lectionary Team.