Full Stack Python (online open book) has a lot of general information on creating a "production Python web application".
See Django. This is the only one I've actually used any amount so far.
Unlike Pylons/Pyramid/Turbogears, which use (or have the option to use) SQLAlchemy, Django has its own ORM. Django also has a nice automatic admin interface.
One advantage of using the Django ORM is that you can keep extra information such as labels (translatable) as par of the model.
The Django package is fairly large in size (~7MB), but is not that much more than e.g. Pyramid + its dependencies + SQLAlchemy.
Django appears to have the largest community. For example, going by PyPi numbers (2014-09-19), it has ~10× the number of downloads as Pyramid; the gap with Flask is smaller (~2×). Of course those numbers may not necessarily mean much.
Merger of Repoze.bfg and Pylons.
Merged into Pyramid.
Interesting essay about Pylon's plethora of developer choices: Frameworks Exist for Conceptual Integrity
A micro-framework. Seems to be getting fairly popular.