Hi everyone,
I do have an addon to share. 
I cobbled together an addon that checks collection items for common error patterns I noticed - it’s still very basic but functional … hopefully I find time for future improvements, at the moment it checks for
- Required fields that are empty (can happen if the required attribute was added later)
- CollectionLink field values that link to collection types that no longer exist
- CollectionLink field values that link to collection items that no longer exist
- Image fields with values(urls) that are no longer valid