In addition to a cassock, rochet or surplice, mozzetta, and pectoral cross suspended from a green and gold cord, there are many other episcopal accoutrements.
First, the crosier is a hook-like staff carried in procession and during the Holy Sacrifice of the Mass. It symbolizes the pastoral care of the people in his diocese. A bishop is the shepherd of the diocese, and like a shepherd who carries a staff to guide his flock, so too does a bishop ceremoniously carry a crosier to lead his flock—the people of god.
The earliest known reference of usage is the seventh century. Since the Second Vatican Council, the pope has carried a crosier as a symbol that he is the Chief Shepherd of the Church. Since Pope John Paul II, the pontifical crosier is in shape of a cross.
Zucchettos are small round skullcaps worn by the clergy, specifically prelates in the Catholic Church. The color of the zucchetto corresponds to the office the cleric holds. It had practical purposes back when church buildings were often cold and damp. Clerics were tonsured in the shape of a cross at the crown of the head. When it is cold, the zucchetto warms the head nicely. Today it is used by prelates to complete the clerical attire of cassock, mozzetta, and rochet (which is a white surplice that is worn under the mozzetta along with the pectoral cross). Zucchettos are also worn under the miter when the prelate is dressed for Mass.
A miter is a hat-like object worn on top of a zucchetto on the head of a prelate. It can come in the liturgical colors of the season being celebrated or plain white. It consists of two high, pointed flaps (one in the front, one in the back) that are joined into a headband, and two pieces of material in the shape of a small stole that hangs from the back. Its origins can be traced back to the tenth century and were in full usage by all prelates by the twelfth century. Abbots, though not bishops, function like bishops in their own abbeys that they govern, and therefore have been give the permission to wear a miter. Also, the pope wore a crown known as a tiara to signify his office as Sovereign—not so much in use now; in fact, Pope Paul VI was the last to wear one at his Pontifical Coronation. The tiara has three levels suggesting the three offices of the pope: chief shepherd, sanctifier, and teacher.
A pallium is a circular band of white wool with two hanging pieces that go over the scapular bone of a metropolitan archbishop or the pope. It is decorated with six black crosses. It is worn over the vestments of these prelates at Mass. The pectoral cross is made of precious metal and is often embellished with precious or semi-precious jewels. It is worn over the neck, usually extended on a gold chain worn over the chest (hence the term pectoral) when wearing a black suit jacket or on a chord on a cassock or over Mass vestments. Pectoral crosses are worn by the pope, cardinals, archbishops and bishops, and abbots. Episcopal rings are part of the official dress of prelates including abbots and abbesses and came into usage in the seventh century.
A ferraiola is a large silken cloak worn over a cassock. When clergy used to dress in cassocks and attend functions outside the church, the formal attire would often include a ferraiola. Only a prelate may wear a ferraiola made of silk corresponding to his rank. A priest may wear a black cape, but not one made of silk.