The three main symbols which identify the Cinderella story are the pumpkin enchanted coach, the single glass slipper, and the prince's castle. Other themes you could use are ball gowns, princess hats and crowns, and magic wands. Any of these things could be presented in various forms as unique and charming Cinderella favors.
One realm of possibility is edible treats. You may choose to offer your guests spun-sugar or cake pumpkins (for the magic coach in the Cinderella story) with elegant accents such as confectioner's pearls for a sparkly, magical treat, or peppermint "magic wands" accented with curling ribbon. Candy or gingerbread castles can be accented with personalized "flags" which serve as gift tags. You might also offer fancy iced sugar cookies in the shape of ball gowns, pumpkins, and princess hats packaged in tulle pouches.
The glass slipper is probably the most easily identifiable and romantic symbol from the Cinderella story. Glass slipper party bud vases, paperweights, and charms can be found in catalogues and online to be used as your Cinderella glass slipper wedding favors. You can fill a glass slipper container any number of ways, for example with pastel candies, potpourri, a votive candle, silk rose petals, or with a single bloom.
Magic pumpkins can be found in every form imaginable, and a ceramic pumpkin container or a carved-out miniature pumpkin can be filled with treats such as candy, tea sachets or charms. If you choose to carve out your own pumpkins, rub the insides with lemon juice to keep them fresh longer and dash the outside with a quick brush of iridescent glitter paint to heighten the "magic" of it.
Candles are always popular and elegant wedding favors, and specialty stores have a variety of shapes that may fit the theme, such as castles and pumpkins. You can also turn a taper candle into a magic wand by loosely weaving ribbon over it and letting the flow in strands from the top.
Hats and crowns are a great Cinderella wedding favor if you are looking for the whimsical side of the fairytale. Princess hats can be accented with long, flowing ribbons, and plastic crowns for the princes can be found in bulk in party supply catalogues. Wreath crowns made of ivy or dried flowers can also be dressed up with ribbon or a spray of craft pearls. Present your guests with a hat at their table setting or hanging on their chairs, and see how many of them end up promptly wearing them - along with a big grin.
All of these Cinderella favors are sure ways to delight your guests, whose biggest joy comes from seeing you off to live Happily Ever After.