There are many, many fraction prayers, as they very throughout the liturgical year (e.g., fraction for the Apostles’ Fast and Feast, Lenten Fraction, etc).
Here is a PDF with many of them.
The Syrian Fraction has some very good, explicit affirmations of non-Chalcedonian Christology in it. Granted, it’s not purely “Coptic”, technically speaking (as its name suggests, we borrowed it from the Syrians at some point), but we share the same Christology…
The Syrian Fraction:
Thus truly the Logos of God suffered in the flesh and was sacrificed and broken on the Cross. His soul parted from His body,
while His divinity in no way parted either from His soul or from His body.
He was pierced in His side with a spear; blood and water flowed from Him for the forgiveness of the whole world. His body was smeared in them, and His soul came and was reunited with His body.
On behalf of the sins of the whole world, the Son died on the Cross.
He turned us from the way on the left towards the right. Through the blood of his Cross, He established the reconciliation of the heavenly with the earthly, and united the people with the peoples and the soul with the body.
And on the third day He rose from the tomb.
One is Emmanuel who cannot be divided after the union; there is no division into two natures. Thus we believe, thus we confess, and thus We affirm that this Body belongs to this Blood, and this Blood belongs to this Body.
You are Christ Our God, who for our sake were pierced in Your side with a spear on the heights of Golgotha in Jerusalem.
You are the Lamb of God who take away the sin of the world.
Absolve us of our transgressions and make us stand at Your right hand side.
O God, the Father of our Lord Jesus Christ, who are blessed by the Cherubim, hallowed by the Seraphim, and exalted by thousands of thousands and ten thousand times ten thousand of the rational servants;
who sanctify and complete the gifts and the fullness of the fruits that have been brought to You as a sweet savor; sanctify also all of our bodies, our souls, and our spirits,
so that with a pure heart and an unashamed face, we may call upon You, O God the Father who are in the heavens, and pray, saying,
Our Father…