Form recipes

This issue is to collect Form Design recipes. We already have a page for these related to repeats. As we gather a few more we'll figure out how to organize them and bring them into the docs. For now, if you see an interesting recipe or use case (for example, in the form) leave a note here with a link and any additional info that would be helpful.

Review the existing page for recipes related to repeats and the Form Design use cases mentioned in the issue first. Done means collecting several interesting recipes with links and useful context; the organization and process for bringing them into the docs are intentionally left undecided.

Written by the indexing model from the issue text.