I've used Flask for several dozen projects, mostly in the data science space. I combined the reusable bits to create http://flask-diamond.org - and I've written lots documentation to help people get work done using it.

Flask-Diamond establishes some common practices so that you are not starting from scratch for each and every new Flask app. In a research context, I might scaffold multiple new apps per month, so this has been a huge time saver for me. This has also made Flask teamwork much easier.