Are there any Antipope Saints aside from Hippolytus of Rome? Have any antipopes other than Antipope Hippolytus of Rome ever been canonized as saints by the Roman Catholic Church?
Only one other antipope than Hippolytus of Rome is considered a saint in the Catholic Church.

The antipope Felix II has been given the status of a saint in the Roman Martyrology with a feast day of July 29.


  According to the "Liber Pontificalis", which may be registering here a reliable tradition, Felix built a church on the via Aurelia. It is well known that on this road was buried a Roman martyr, Felix; hence it seems not improbable that apropos of both there arose a confusion (see FELIX I) through which the real story of the antipope was lost and he obtained in local Roman history the status of a saint and a confessor. As such he appears in the Roman Martyrology on 29 July. - Catholic Encyclopedia