Michael pointed me towards the FSSP website on which there is this prayer for priests:
“O Lord Jesus, born to give testimony to the Truth, Thou who lovest unto the end those whom Thou hadst chosen, kindly hear our prayers for our pastors.
Thou who knowest all things, knowest that they love Thee and can do all things in Thee who strengthen them.
Sanctify them in Truth. Pour into them, we beseech Thee, the Spirit whom Thou didst give to Thy apostles, who would make them, in all things, like unto Thee.
Receive the homage of love which they offer up to Thee, who hast graciously received the threefold confession of Peter.
And so that a pure oblation may everywhere be offered without ceasing unto the Most Holy Trinity, graciously enrich their number and keep them in Thy love, who art one with the Father and the Holy Ghost, to whom be glory and honour forever. Amen.”
Please do follow the link (there are partial indulgences ).