Looking for a filling that doesnt need to be refrigerated...costumer has an outdoor party and would like something else besides buttercream.
The "sleeve" fillings like Bavarian Cream and Chocolate are stable without refridgeration. Chocolate ganache is also.
Ganache works great, whether it's dark, milk or white chocolate. There's also fruit filling sleeves, pie fillings, homemade caramel, buttercream with Lorann flavorings or candies/chocolate chips/peanut butter/instant pudding mixed in (changes the texture completely), Bettercream or Whip'n'Ice ... as a matter of fact, I only very very rarely use fillings that require refrigeration, but I still never ever use straight-up buttercream.
I've had good luck w/ sweetened cream cheese or mascarpone w/ fresh berries, fruit pie filling, jams, currant jelly, apricot glaze, lemon/lime curd...