1. To-do list
Helpinator allows to add to-do tasks to topics. You can add a task inside a topic editor and review them later in the global project to-do list.
To-do in topic editor
Global to-do list
2. Check links
"Check links" tool allows to check all topics for broken links.
3. Global Spellcheck
Global spellcheck is a kind of Quality Assurance tool that checks spelling in all topics of the project and allows to fix errors with a couple of mouse clicks.