I know there are several prepackaged snacks that are gluten free and snack credit eligible.
I also know that Jack Jack's Nom Nom Cookie (no gluten free) is now available at Hollywood Studios, I only mention this because it was originally at DCA only and the cart that sells it also sell a gluten free cookie that everyone (even those who don't need gluten free) raves about, it is a blackberry cookie I believe and while it is baked on site, it is baked on separate equipment and has its own packaging to avoid cross contamination, but I do not know if that cookie has made its way to Disney World or not, just a heads up to ask about it.
All fruit flavors of Dole Whip are Vegan and should be gluten free, but double check. I also believe the Dole Whip Float would be gluten free, but again double check.
Erin Mckenna's Bakery in Disney Springs has many gluten free options (I believe everything there is gluten free as I recall, but ask to make sure), additionally according to their website, you can find their products elsewhere at Disney World as follows:
- The Beach Club Marketplace at Disney’s Beach Club Resort.
*Chocolate Chip Cookies, Cinnamon Sugar Donuts, Chocolate Dipped Donuts, Mini Brownie Cupcakes.
- The Boardwalk Bakery at Disney’s Boardwalk.
*Mini Brownie Cupcakes.
- The Gardens Kiosk at Disney’s Animal Kingdom.
*Chocolate Chip Cookies, Mini Brownie Cupcakes.
- The Mara at Disney’s Animal Kingdom Lodge.
*Mini Brownie Cupcakes.
- Landscape of Flavors at Disney’s Art of Animation Resort.
*Mini Brownie Cupcakes.
- Everything Pop at Disney’s Pop Century Resort.
*Mini Brownie Cupcakes.
I am sure there are many, many others, these are what I know of off the top of my head.