Core Components

Core Components ship with WordPress. This package includes a library of generic WordPress components to be used for creating common UI elements shared between screens and features of the WordPress dashboard. Some examples include Button, ColorPicker, and TextControl.

Example showing Button component precompiled code, rendered code, and browser display.

Code and Documentation

You can find the actual code in the Gutenberg GitHub repo
Documentation is available in the Block Editor Handbook
A great reference is the Gutenberg Storybook
https://wp-gb.com/ maintains a searchable list of components with screenshots and code samples.

What components are available in each WordPress version?

Switch to the branch for the version of WordPress in our environment by looking for the branch name that starts with `wp/<version>`

Components in each WordPress release can be browsed in Github by changing to the branch for each release. This will let you see the components, their code, and the documentation for each. The Block Editor Handbook in contrast is always updated and reflects the latest version of WP so it includes components we may not have access to yet and properties, features, etc that might be only in the latest release.

WordPress 5.8 Components:

Components Package

The components package located in gutenberg/packages/components contains the majority of the components you’ll want to explore and use in your blocks.

For 5.8 you can find it here: https://github.com/WordPress/gutenberg/tree/wp/5.8/packages/components

Block Editor Package

The Block Editor package located in gutenberg/packages/block-editor contains some components that you may also want to use. These components are typically related to the overall block editor UI. Components like link-control, InspectorControls, InnerBlocks, and rich-text live in this package.

For 5.8 you can find it here:
https://github.com/WordPress/gutenberg/tree/wp/5.8/packages/block-editor/src/components

Inner Blocks – allows blocks to have nested child blocks
Inspector Controls – allows you to add components to the sidebar for the selected block
Rich-text – A very commonly used component for allowing users to enter and format content. Used in blocks like Paragraph blocks.

More at Getting Started: Importing Components