In the 1962 typical edition of the Roman Missal there is a votive Mass for the Unity of the Church.
In light of the meetings involving the emanations of penumbras of the SSPX movement, I will share with you today the
Deus, qui errata corrigis,
et dispersa congregas,
et congregata conservas:
quaesumus, super populum christianum
tuae unionis gratiam clementer infunde:
ut, divisione reiecta,
vero pastori Ecclesiae tuae se uniens,
tibi digne valeat famulari.
O God, Thou who dost correct errors,
and who both gather the scattered,
and preserve what has been gathered:
we beseech Thee, kindly pour out
upon the Christian people the grace of Thy union;
so that, once the division is rejected,
uniting itself to the true pastor of the Church
it may may able to serve Thee worthily.