Jinja2 is certainly not the only templating package in existence. You can find a maintained list of Python templating engines at https://wiki.python.org/moin/Templating.

Like frameworks, different engines exist because of differing philosophies on what makes a good engine. Some feel that logic and presentation should be absolutely separate and that flow control and expressions should never be available in templates, providing only valued substitution mechanisms. Others take the opposite approach and allow full Python expressions within template markup. Others, such as Jinja2, take a middle ground approach. Some engines also use different schemes altogether, such as XML-based templates, or declare logic via special HTML tag attributes.