The Fat Free Framework or as its also know F3 is a very slim lightweight micro php framework, and not as bloated as Zend, Symfony, Laravel, Codeigniter, etc. Its still a very powerful framework, that allow you a lot of freedom. Follow the normal "mvc" conventions, or created your own, it includes a RESTful routing engine too. It has small ORM that supports out of the box MySQL, SQLite, MSSQL/Sybase, PostgreSQL, DB2, and MongoDB. Also has out of the box support for multi-lingual applications, which will come in handy.
This is a project template that you can used to start with F3 framework. It integrated with valitron validation, domPdf library, PDO class, and bootstrap + jquery for the front end.