Digital Tools for Spelling?

Part of my job is to find digital tools teachers can integrate into their classes.  I love the research and being able to play around with different apps and sites to see what I like as well as the chance to help teachers use computers in their classes.

Our elementary students (grades 2-6) are entering a spelling bee, and my principal asked me to find some tools to help the kids practice.  (I did joke with her that this is pretty low on the SAMR ladder, but I still get to help kids practice their spelling. No worries...)

I'm not supremely happy with anything that I find. I suppose any of these will help students work with words, which is the main goal.  Most of the tools I find are in the following categories:

1. Teacher types in the list, and students practice the list. (Pretty laborious, especially if a teacher has to type the same list into 20 iPads.)
2. Students create words from randomly placed tiles -- like Boggle. (Students tend to try random letter combinations rather than actual words.)
3. Students use pre-created word lists to play review games.  (I like that option, but sometimes the games are cheesy.)

What digital spelling tools do your students and teachers enjoy using in class?