We do have communion without a mass, Good Friday being one example.
I don’t know about the current Novus Ordo, although I shall look into it, but in the Vetus Ordo, the Tridentine Mass, Good Friday did have a Mass, the Mass of the Presanctified, which corresponds to the Mass of the Presanctified in the Eastern Orthodox tradition and to the Signing of the Chalice in the Syriac Orthodox liturgy (which at present is being celebrated only by the Malankara Independent Syrian Church). There were, before Turkocratia, presanctified liturgies in the Armenian and Coptic Orthodox liturgies, and it is thought that the curious liturgy in the Coptic Euchologion known as the “Filling of the Chalice” is one such liturgy (I had misread it, and incorrectly assumed it was a liturgy for consecrating additional bread and wine in the event the celebrants ran out of the sacred Body and Blood of our Lord).
Now, there are two surviving forms of the Liturgy of the Presanctified in Eastern Orthdooxy: the Presanctified Liturgy of St. James, a new critical English and Church Slavonic edition of which, along with the Divine Liturgy of St. James, was recently published by Holy Trinity Monastery in Jordanville, New York (which is also the main ROCOR seminary), where this Presanctified Liturgy has been celebrated in recent years, but this one of those obscure Eastern Orthodox liturgies not widely used, and indeed, sadly most Orthodox Christians are not aware they exist, even those who have attended the Divine Liturgy of St. James, which itself rare, but some churches do celebrate it on the 23rd of October each year. The Presanctified Liturgy of St. James, along with the Divine Liturgy of St. Mark, the Divine Liturgy of St. Peter and indeed the Divine Liturgy of St. James itself is one of those liturgies that ideally would be widely celebrated by Orthodox parishes, but which at present are sadly confined to occasional celebrations in monasteries, seminaries and some cathedrals where the bishop has an interest in them, almost on a par with the beautiful Mozarabic Rite liturgy, which in the 19th century was still celebrated in a handful of parishes in Toledo, but is now celebrated only in a chapel specifically set aside for that purpose, and also, I have heard, in a nearby monastery, although Pope John Paul II did celebrate the liturgy in St. Peter’s Basillica in the 1990s, but despite this endorsement, the ancient liturgy of Spain survives outside the museum set aside for it only in certain aspects of the traditional marriage liturgy as it was celebrated in Mexico and other Latin American countries. Likewise, the traditional, pre-1969 recension of the Ambrosian Rite liturgy of Milan is celebrated in only one church that was reserved for that purpose, which is inadequate for the millions of people who observe it, since the Ambrosian RIte is the second most widely used liturgical rite in the Patriarchate of the West. But I digress.
Whereas the seldom-celebrated Presanctified Liturgy of St. James is a normal liturgy, intended to be celebrated in the morning (customarily following Terce and Sext) and is no longer in common use, the Presanctified Liturgy of St. Gregory Diologos, also known as Pope St. Gregory the Great, is used by nearly every Eastern Orthodox parish, and also by most Byzantine Rite Catholic churches, and is a Vesperal Liturgy, which is traditionally preceded by the third, sixth and ninth hours during Holy Week (albeit it is usually served in the morning, and it is only served on Monday, Tuesday and Wednesday, with the Vesperal Divine Liturgy of St. Basil on the morning of Maundy Thursday and Holy Saturday, and no Eucharistic liturgy at all, nor any partaking of the liturgy, on Great and Holy Friday) and which is actually served in the evening during the Great Lent.
The wording of the core of this liturgy is identical to that of the Mass of the Presanctified as it was celebrated on Good Friday until 1955, which makes sense, as the Roman Mass of the Presanctified, along with Gregorian Chant, was recognized as one of the liturgical contributions of Pope St. Gregory the Great. in 1955, Pope Pius XII engaged in an ill-advised modification of the Paschal Triduum, in which he changed the liturgical color of Good Friday from black to red (historically, black vestments are traditional in Holy Week except on Holy Thursday, in not only the Roman Catholic Church and the Eastern Orthodox Church, but also the Coptic Orthodox and Syriac Orthodox churches - I will verify the Armenian practice but I expect it is the same), and completely rewrote the Mass of the Presanctified, and he also moved the Paschal Vigil Mass from its traditional time on Saturday morning (which sounds counter-intuitive until one understands the reason for it, which is to facilitate the Midnight Mass on Easter Sunday, which is preceded by Paschal Matins, and in the Roman Rite under Pius XII, an attempt to restore this was confused, resulting in celebrating Paschal Vigils in the evening of Holy Saturday.
The problem is of course that Matins for Holy Saturday is a traditional part of the Good Friday liturgy, and is traditionally the time for the triumphant hymns celebrating the victory of Christ on the cross, after the more solemn portion of the liturgy being the Royal Hours and Vespers (the Tenebrae services in the Latin Rite correspond to the Twelve Gospels Service, which features lighting similar to that of the Tenebrae Hearse, which happens on Maundy Thursday at Vespers, which is the start of Good Friday, and at Vespers on Good Friday, which is the start of Holy Saturday). Also, Pope Pius XII reduced the number of Old Testament prophecies read at Paschal Vigils from twelve to four (at least fourteen prophecies are still read in the Vesperal Divine Liturgy on the morning of Holy Saturday in the Eastern Orthodox and Byzantine Rite Catholic churches).
The reason for the large number of Old Testament lessons at these masses is twofold: this is the occasion for reading the clearest prophecies in the Old Testament of the passion and resurrection of Christ our True God, and also, these were, and still are, read during the baptism of catechumens (for this reason, during the Divine Liturgies and Presanctified Liturgies of Holy Week, in addition to the Litany for the Catechumens, an extra set of prayers, the Litany for the Energumens, is read - Energumens, or in English, “Those Awaiting Illumination” are catechumens who have completed their Catechumenate and are ready to receive Illumination in the form of Baptism. Indeed, additional prophecies would be read if needed according to the number of catechumens being baptized. There is a specific benefit to those catechumens who are being baptized hearing these prophecies at this time, as it helps to eviscerate any remaining doubt as to the truth of the Passion and Resurrection of our Lord, God and Savior Jesus Christ.
Now, I was under the impression that the Novus Ordo had restored the Mass of the Presanctified in part, so that the wording of it once again resembled that of the Liturgy of the Presanctified of St. Gregory the Dialogist, but your statement of “receiving communion without the mass” is concerning.
Historically, in the Roman Rite, only the priest would partake of the Eucharist at the Mass of the Presanctified, and at Solemn High Masses - I am not sure if the latter remains the case even in the Traditional Latin Mass, and it is not the case in the Missa Cantata, which has many similarities with a High Mass, such as the reading of the Last Gospel and the omission of the Leonine Prayers, despite in terms of the actual text of the liturgy being closer to a Low Mass, which was the means by which most Roman Catholics partook of the Eucharist. I do not object to a change in this (for that matter, I think Vatican II was right to introduce communion in both kinds, but unfortunately the Concilium under Annibale Bugnini failed us here as well, by not mandating communion in both kinds, which is almost as much of a failure in my opinion as their ignoring the instruction of Sacrosanctum Concilium to ensure that Latin remained an integral part of the mass - as i have said repeatedly, the only part of Sacrosanctum Concilium I disagree with was the strange decision to suppress the hour of Prime, particularly given its historic significance; as i see it, merging Lauds and Matins into a single office would have made much more sense, particularly insofar as the Western Rite is unique in keeping these separate; specifically, Lauds could have been made a part of Matins, but I digress.
However, Sacrosanctum Concilium did not call for anything quite as radical as what Pope Pius XII did to the Paschal Triduum, which had the effect of destroying the historic continuity between it and the Byzantine Rite liturgy in use by Eastern Catholics and Eastern Orthodox. And this is particularly tragic in the case of the Mass of the Presanctified, which is the one place where the Roman Rite and the Byzantine Rite were word-for-word identical, with a clear attestation to Pope St. Gregory the Great, who was the last Roman Catholic Pope to be venerated as a major saint in the Eastern Orthodox church.