Jinja2 - Jinja2 is a template engine written in Python.
mustache - Mustache is a simple web template system with implementations available for ActionScript, C++...
Hamlet - Hamlet is an open source reactive templating system.
Handlebars - Handlebars is a JavaScript template library that is, more or less, based on ...
Pug - Pug is a robust, elegant, feature rich template engine for Node.js
EJS - An open source JavaScript Template library.