zodiac fairies would be cool. fairies aren't often used in zodiacs either

You know, a set of fairy tarot cards would be awsome!

well ok, i have vote for 4 elements but i vote too for 7 sins and zodiac sings! ^^ you can make 3 series don't you?

hard choice , but I like it ... wicked!

Argh! such a hard decision.

The 7 deadly sins would be very interesting done as fairies!

While I like the idea of the 7 deadly sins or as an alternative heavenly virtues, it might be more fun to give them a distinctively fey twist.

For instance, a fairy might have a far different idea of what are sins, such as being bored - so may adventures to do, blandness - who can stand plain ol food when there's banana split, sundaes and chocolates abound, or dullness - a little pixie dust improves everything.

Another take would be to follow a fairy though her "day" staring with morning and showing her adventures until returns to bed.

I'm going to vote for the 7 Deadly Sins. People often depict fairies as very nice. Depicting them as NOT very nice would be cool!

Of course, I like pretty much all the ideas that you gave Go for it!