[gregod]

You might also want to look at the very comprehensive office 365 react components from MS which is build on. https://github.com/OfficeDev/office-ui-fabric-react

Meant for developing Sharepoint/Office Apps but released under MIT License (Only the custom Microsoft Fonts are restricted but easily replaced)

[jlebrech]

i remember when you'd get a fully featured ui library when you bought a compiler.

[smacktoward]

Nowadays the compilers are free. I guess you get what you pay for.