My roommate decided partway through this week that she wanted to run a workshop on making favors, so that our non-combatant members could have something to make them feel more involved in wars. So, she began researching, and decided to make a favor to give to me to carry into battle as well.
Much of what we could find on favors has to do with the practice of giving them in the SCA. In the SCA, there is actually a difference between favors and tokens. Favors are given between people who are romantically involved, and in SCA symbolize this involvement. Tokens, on the other hand, can be given to symbolize friendship, group membership, or a non-romantic connection. As best as I can tell, the only way to determine whether something is a token or a favor is by the way in which it is presented to the fighter.
Historically, a lady could support a knight or page through largess, which included gifts that would improve his ability to fight. This could be things like armor, horses, or gear. Gifts indicating a love relationship were not very common, but did certainly exist.
Some ideas for favors:
1) SCA uses small squares of fabric worn on the belt, but there is no historical evidence for this
2) handkerchief
3) sleeves (sleeves used to just tie on to a bodice)
4) jewelry
5) strings of beads
6) a glove (evidence for this from Upsala)
7) veils
8) shifts/chemises (how????!?!)
9) girdle (from the tale of Gawain and the Green Knight)
10) flags/banners
Where favors could be displayed:
hat (or hatband)
on a lance
pinned to a sleeve
rings on the little finger of the left hand
SCA tokens are worn on a belt
Women could also accept favors from men:
"The Countess of Champagne was also asked what gifts it was proper for ladies to accept from their lovers. To the man who asked this the Countess replied, 'A woman who loves may freely accept from her lover the following: a handkerchief, a fillet for the hair, a wreath of gold or silver, a breastpin, a mirror, a girdle, a purse, a tassel, a comb, sleeves, gloves, a ring, a compact, a picture, a wash basin, little dishes, trays, a flag as a souvenir, and to speak in general terms, a woman may accept from her lover any little gift which may be useful for the care of the person or pleasing to look at or which may call the lover to mind, if it is clear in accepting the gift she is free from all avarice.'" - Andreas Capellanus