Throughout the Church’s history there have been many members of the hierarchy who were members of Religious Communities. The present pope is a member of the Society of Jesus (Jesuits) and the first from that Order elected to the papacy. One of the oldest Orders in the Western Church is the Order of St. Benedict. Many monks have been made bishops and quite a few have been raised to the Sacred Purple as Cardinals. The following is by no means exhaustive but gives a sampling of some of the Benedictine Cardinals in recent history. (My gratitude to the fine website called Araldica Vaticana for many of these examples.
Enjoy!

Gregory Cardinal Chiaramonte, OSB (later Pope Pius VII)

Jean Cardinal Pitra, OSB

Placido Cardinal Schiaffino, OSB Oliv

Celestine Cardinal Ganglbauer, OSB (Archbishop of Vienna)

Aidan Cardinal Gasquet, OSB (Vatican Archivist)

Bl. Giuseppe Cardinal Dusmet, OSB (Archbishop of Catania)

Kolos Cardinal Vaszary, OSB (Primate of Hungary)

Francisco de S. Luiz Cardinal Soraiva, OSB (Patriarch of Lisbon)
NOTE: Cardinal Soraiva also had a version of his arms with a galero but also used the triple tiara as was customary for the Patriarchs of Lisbon until very recently.

Domenico Cardinal Serafini, OSB

Ildephonse Cardinal Schuster, OSB (Abbot of St. Paul Outside-the-Walls and later Archbishop of Milan)

Justinian Cardinal Seredi, OSB (Primate of Hungary)

Joachim Cardinal Albareda y Ramoneda, OSB (Vatican Librarian)

Benno Cardinal Gut, OSB

Basil Cardinal Hume, OSB (Archbishop of Westminster)

Hans Herman Cardinal Groer, OSB (Archbishop of Vienna)

Paul Augustine Cardinal Mayer, OSB