Related: Form Builder, Layouts and Web Template Repositories and Dashboard
Project: have a page builder like https://livecomposerplugin.com/features/ for Tiki.
Perhaps using H5P
H5P builds interactive contents of various types which can be integrated into any web page online. It's not exactly a page builder like Visual Composer.
there are also https://www.openhub.net/p/VvvebJs for the same goal
Concept
The idea is to give user an easy to use visual drag & drop interface to build Tiki pages. The need for such an editor was felt when composing a bit complex TIKI pages to build designed PDF files. As without such an editor, a user having good HTML/CSS skills only can compose a rich design content page.
Examples on WordPress
Ideal page builder is https://vc.wpbakery.com/ Visual Composer.
https://livecomposerplugin.com/ is an open source alternative for Visual Composer. However its not as rich in features. One negative for LiveComposer is that some features are in paid addons. Both of the plugins are for Wordpress but since LiveComposer is open source we might be able to modify it to work with Tiki.
https://elementor.com/ is another open source - its looks better than LiveComposer in user interface but also has a pro version and is for Wordpress.
http://gettailor.com/ its on GitHUB another opensource page builder for Wordpress - Tutorial on Youtube https://www.youtube.com/watch?v=tfMyLMuaXjI
More options here http://alternativeto.net/software/visual-composer/?license=opensource
INDEPENDENT PAGE / SITE BUILDERS
https://www.silex.me/ Its a WP competitor a drag and drop page / site builder. Its open source and available on Github . Check Live DEMO at https://editor.silex.me/
http://mashable.com/2013/10/20/bootstrap-editors/#2CZnKh8H8aqI
Sub project: make it easier to generate nice PDFs from web content
Drupal
VvvebJs
http://www.vvveb.com/vvvebjs/editor.html (Very nice!)
GrapesJS
https://github.com/artf/grapesjs
https://grapedrop.com/
https://www.youtube.com/channel/UCcSiVsVcplkgubrdebikZng