SharePoint Framework web part, Teams tab, personal app, app page samples

List Formatting Samples for use in SharePoint and Microsoft Lists

Modern SharePoint Starter Kit - End-to-end showcase solution to get started with modern experiences.

Code samples and developer content targeted towards SharePoint Framework client-side extensions. https://aka.ms/spfx-extensions

Repository for SharePoint development reusable solutions

A Yeoman Generator for Microsoft Teams

Reusable SPFx property pane controls - Open source initiative

Microsoft Office JavaScript API Reference