Elder Ieronymos of Aegina was clairvoyant and also a member of the GOC. Abp Auxentios served his funeral (source: Fr Maximos Marretta). New Calendarists actually had the gall to market him as one of theirs too, but the life published by Holy Transfiguration puts to rest that nonsense in their introduction. The author, Peter Botsis, interestingly is a New Calendarist. He downplays Fr Ieronymos' role in the GOC, although he doesn't explicitly deny it.
He didn't join the GOC until late, although he had always served on the Old Calendar, and the New Calendarist authorities left him alone because of his reputation. But once the Metropolitan forced him to concelebrate with him on the New Calendar, Fr Ieronymos left the State Church and joined the GOC. Anastasios told me that reports of his clairvoyance didn't appear until after he joined the True Church, which is very interesting.
Fr Ieronymos knew Fr Niphon, who was the brother of Met Petros of Astoria, and after his repose he left his spiritual children in Fr Niphon's care. Fr Niphon himself has been called a saint by everyone I've met who remembers him. A friend of mine told me that he displayed true humility.