"A community of designers and developers collaborating to build a UI framework for enterprise web applications."
As developers, creating web UI's is a challenge. Patternfly is used in almost all Red Hat products with a web UI. Use, contribute and participate in the Patternfly community and help build the next generation UI front end framework. Check out the pattern library at https://www.patternfly.org/pattern-library/
They have prototype HTML/CSS/JS for every conceivable enterprise application widget you can think of and it's all very pretty and professional looking - no more hunting around for free UI toolkits with shady advertising and outrageous pricing....
Interesting news, the next-genneration Patternfly (release 4) will focus on React and drop support for Angular.