Agile Toolkit (ATK) offers you a full-stack UI framework for building your Web Apps faster. It is built on top of 4 major components: Core, DSQL, Data and CSS (see below). ATK implements MVP architecture with major focus on "code reuse" and offers you all the tools to build a responsive Web App in just a few minutes.
If you are new to Web Development, start by learning Agile Toolkit.
Visit Agile Toolkit GitHub. License: MIT
Agile Platform links thousands of independent Agile Toolkit developers by allowing them to share and sell their add-ons, widgets and themes. Platform indegrates directly into your local copy of Agile Toolkit to make set-up process simpler and save you even more time.
Agile Platform will be released by Jan 2017. Sign-up for early access.
Application performance depends on clean business logic design and efficient interactions with database. Agile Data solves efficiency woes of web apps built on Agile Toolkit. You can also use it separatly.
Visit Agile Data on GitHub. License: MIT
You do not see many UI add-ons for PHP frameworks because each web app implements UI differently. Agile Toolkit apps and add-ons use same CSS framework, making all UI consistent and themeable.
Visit Agile CSS on GitHub. License: MIT