For a complete integration with Django templates I found this: Yz-Javascript-Django-Template-Compiler. I never used it myself and unfortunately it looks a bit unmaintained.
Swig is a fast JS django-like templating engine.
Pure is a compiled JS templating tool that, with a bit of thinking, could work well with Django I think because templates are just normal valid HTML.
Other interesting JS template libraries:
- Handlebars (an extension of Mustache)
- Underscore