mustache - Mustache is a simple web template system with implementations available for ActionScript, C++...
jquery-template - A template plugin for jQuery. Allows templating without cluttering JavaScript code with markup.
Jinja2 - Jinja2 is a template engine written in Python.
Pug - Pug is a robust, elegant, feature rich template engine for Node.js
Handlebars - Handlebars is a JavaScript template library that is, more or less, based on ...
Eta JS - Application and Data, Languages & Frameworks, and Templating Languages & Extensions