Several Bishops have routinely exercised biritual faculties granted before their ordination to the episcopacy, and technically, all bishops may celebrate in any Catholic rite… custom is that they only celebrate those rites which they have either training in or parishioners from. The Bishop of Denver, nominally Roman (and originally a Roman priest) is also bishop for a parish of the Russian Catholic Church, and can be expected to serve the Byzantine HDL of St. John and HDL of St. Basil (as dictated by the Calendar). Likewise, one of the bishops in NYC. And Moscow.
ANd the Bishops of the Ethiopian Catholic Church also have Roman Rite parishes, and celebrate the Roman Mass in those, and the Ethiopian Divine Liturgy in the Ethiopian Rite Parishes.