Items in use presently, even if only rarely (such as the camauro or papal cappello romano), will not be shown here.
The Fanon
A shoulder-cape worn by the pope alone, consisting of two pieces of white silk ornamented with narrow woven stripes of red and gold; the pieces are nearly circular in shape but somewhat unequal in size and the smaller is laid on and fastened to the larger one... The front part of the fanon is ornamented with a smallcross embroidered in gold...
The fanon is like an amice; it is, however, put on not under but above the alb. The pope wears it only when celebrating a solemn pontifical Mass, that is, only when all the pontifical vestments are used. The manner of putting on the fanon recalls the method of assuming the amice... After the deacon has vested the pope with the usual amice, alb, the cingulum and sub-cinctorium, and the pectoral cross, he draws on, by means of the opening, the fanon and then turns the half of the upper piece towards the back over the pope's head. He now vests the pope with the stole, tunicle, dalmatic, and chasuble, then turns down that part of the fanon which had been placed over the head of the pope, draws the front half of the upper piece above the tunicle, dalmatic, and chasuble, and finally arranges the whole upper piece of the fanon so that it covers the shoulders of the pope like a collar.
The fanon is mentioned in the oldest known Roman Ordinal, consequently its use in the eighth century can be proved. It was then called anabolagium (anagolagium), yet it was not at that period a vestment reserved for the use of the pope. This limitation of its use did not appear until the other ecclesiastics at Rome began to put the vestment on under the alb instead of over it, that is, when it became customary among the clergy to use the fanon as an ordinary amice. This happened, apparently in imitation of the usage outside of Rome, between the tenth and twelfth centuries; however, the exact date cannot be given. But it is certain that as early as the end of the twelfth century the fanon was worn solely by the pope, as is evident from the express statement of Innocent III (1198-1216). The vestment was then called an orale; the name of fanon, from the late Latin fano, derived from pannus, (penos), cloth, woven fabric, was not used until a subsequent age. Even as early as the eighth century the pope wore the fanon only at solemn high Mass...
(The Catholic Encyclopedia)
The Falda
The falda was a long alb-like garment that formed a kind of train typical of certain types of earlier dress for both men and women. It is worn under the alb.
The Mantum
The mantum or papal mantle differs little from an ordinary cope except that it is somewhat longer, and is fastened in the front by an elaborate morse. In earlier centuries it was red in colour; red, at the time being the papal colour rather than white. In the eleventh and twelfth centuries the immantatio, or bestowal of the mantum on the newly elected pope, was regarded as specially symbolical of investiture with papal authority: Investio te de papatu romano ut praesis urbi et orbi, "I invest you with the Roman papacy, that you may rule over the city and the world" were the words used in conferring it at the Papal Coronation. The use of the mantum by the popes ceased under Paul VI, following the reforms of Vatican II.
The Subcinctorium
From the Catholic Encyclopedia:
Very similar to the maniple in form and nature is the subcinctorium, an ornamental vestment reserved to the pope. It is worn on the cincture; on one end is embroidered a small Agnus Dei and on the other a cross. The pope wears it only at a solemn pontifical Mass. The subcinctorium is mentioned under the name of balteus as early as the end of the tenth century in a "Sacramentarium" of this date preserved in the Bibliotheque Nationale at Paris (f. lat. 12052). It is mentioned under the name proecinctorium about 1030 in what is known as the "Missa Illyrica". Later it was generally called subcinctorium. In the Middle Ages it was worn not only by the pope but also by bishops, and even in a few places by priests. However, it gradually ceased to be a customary vestment of bishops and priests, and in the sixteenth century only the popes and the bishops of the ecclesiastical province of Milan wore it. The original object of the subcinctorium was, as St. Thomas explicitly says, to secure the stole to the cincture. But as early as about the close of the thirteenth century, it was merely an ornamental vestment.
Papal Slippers
For their outdoor shoes, Popes used to wear red leather shoes with a cross upon them. The cross was abandoned under Paul VI though the red leather continued until the pontificate of John Paul II. They have since been revived under Benedict XVI.
Here are the traditional sort of outdoor shoes with the cross upon them:
For indoor use inside the papal household however, the pope would wear slippers of either red cloth with an embroidered cross upon them.
(Above image of John XXIII's Papal Slippers courtesy of Orbis Catholicus)
The Papal Tiara
One of the most familiar of the unused items of papal vesture is of course the tiara or "Triregnum." It remains a familiar symbol of the papacy though it hasn't been used since the pontifical of Paul VI.
We leave with final image that shows Pope Pius XII at the papal throne.