There are no groups that I know of who have returned to the Holy See. Individuals have, I know of only two priests who derived their orders from Old Catholic lines who were allowed to enter into a Catholic Seminary to assure a proper formation, (after they returned to the Catholic Church. and waited for two years of discernment) one is in Italy, and was once attached to a group that followed one of the supposed Marian Apparitions here in the U.S.A. that was pronounced by the Church to not be authentic. I won’t give any more details, as it is his story to tell.
Historically however O.C. Clergy, at least outside of the Netherlands and Germany who are received into or return to the Church are recieved as Laymen, and not permitted to function. Since most would not need an Ordinariate, As the more Catholic of the O.C. churches either use the EF or the OF,as such they do not have a Liturgical Patrimony like that of the Anglicans, or Eastern Catholics, there would be no real need to set up an Ordinariate.
There are only two types of ordinariates that I know of, the first is for the Military in each country, as when a serviceman or woman is stationed to a base, within or outside of their country of origin, and they seek the sacraments from a Military Chaplain, these priests need to have faculties making it difficult to always and everywhere be able to obtain them. So they have their ordinary who is a Bishop assigned the task for each country which has the Military Ordinariate.
As for the Anglican Use. Those who are recieved into the Church, are fully Catholic, and allowed to retain those liturgical practices that are unique to Anglicanism, but also completely Catholic. Having their Ordinariate, they can maintain those practices, which are different from local Eastern Catholic, or Roman Rite practices.
Since the Ordination of Women and other issues by many O.C. groups, and the fact that outside of the Polish National Catholic Church, and the Dutch/German Old Catholics, most others have little or no formation or structure, even the largest in the US and Canada, (Christ Catholic Church) has any number of clergy who vary from O.F. Liturgies in Latin, to Charismatic very Low Church protestant style services. I’ve met a couple of their bishops who have little or no formation, who are married to their third or fourth wife, and are only bishops in the CCC because they were bishops somewhere else. The PNCC,and the Dutch/German O.C. do have a fairly good formation, even if it is not 100% in line with the Catholic Church’s teachings. There has been dialogue with the PNCC, and a limited intercommunion agreement was made a decade or so ago if there was grave reason and a layman of one group or the other could not recieve the sacraments from a priest of his own Church.