Today is the feast of the Protection of the Theotokos.

We also commemorate many saints that are associated with sacred music and hymnography. Here's a thread about them

The 1st and most important musical saint is the Prophet King David, forefather of Christ and the author of the Psalter.

While modern parish practice abbreviates most chanting of Psalms, monastery services are still be mostly comprised of Psalms and interpolated verses from it.

Next, the Saints celebrated today

St. John Koukouzelis was a professional court singer, and a graduate of the Royal Academy of music. However, he didn't like fame and fortune, so he fled to Athos and tried to hide his talents.

More of his life below

https://www.oca.org/saints/lives/1999/10/01/102832-venerable-john-koukouzelis-the-hymnographer-of-mount-athos

St. Roman the Melodist

He composed the Paschal Troparion among many others

He was not always talented, but prayed to the Theotokos to have a voice worthy of praising the Lord

There's a Orthodox musical society dedicated to him

https://www.oca.org/saints/lives/2020/10/01/102826-venerable-romanus-the-melodist-sweet-singer

https://www.saintromanos.org/ 

St Gregory the Choirmaster

He was the leader of the singers of Great Lavra on Athos, and St. John Koukouzelis was one of his singers

The Theotokos appeared to him to ask that "All Creation Rejoices in Thee" be sung at the Liturgy of St. Basil the Great

https://www.johnsanidopoulos.com/2015/10/saint-gregory-domestikos-of-great-lavra.html

St. Cosmas the Poet

Along with composing many of the most important canon hymns we use, he is most known for "It is Truly Meet", which would eventually be completed by none other than the Archangel Gabriel a few centuries later

https://www.johnsanidopoulos.com/2017/10/saint-kosmas-poet-bishop-of-maiuma.html

St. John of Damascus

On top of being one of the greatest theologians in history, he was a master hymnographer. He composed the Paschal Canon, and along with his friend St. Cosmas, mastered the form of the canon which is used to this day in the Church

https://www.oca.org/saints/lives/2016/12/04/103473-martyr-john-of-damascus

St. Joseph the Hymnographer

While in prison, St. Nicholas appeared and gave him a scroll with a prayer. Like St. John in the Apocalypse, he ate it, and sang "How sweet are Thine oracles to my throat", and escaped.

He composed most canons of the Menaion

https://www.oca.org/saints/lives/2018/04/04/100984-venerable-joseph-the-hymnographer

Finally, Sts. Geronty & Leonty Canonarchs of the Kiev Caves

During vigil, one said "Bring my soul out of prison, that I may give thanks to Thy name", and died

The other finished "The righteous await me, for thou shalt requite me"

https://www.johnsanidopoulos.com/2020/04/saint-gerontius-canonarch-of-kiev-caves.html
https://www.johnsanidopoulos.com/2017/06/saint-leontius-canonarch-of-kiev-caves.html

Finally, a nice synaxis icon of many of these saints

If you know of any more, do tell!

https://www.uncutmountainsupply.com/icons/of-saints/by-name/n-o/icon-of-the-synaxis-of-holy-chanters-and-hymnographers-1nc20/