Documentation & Guides:

CSS Shapes - MDN

Overview of CSS Shapes - MDN

<basic-shape> - MDN

shape-image-threshold - MDN

shape-margin - MDN

shape-outside - MDN

CSS Shapes Module Level 1 specification - W3C

CSS Shapes Module Level 2 specification draft - W3C

Blog Posts & Articles:

CSS Shapes 101 - Sara Soueidan

Moving Forward with CSS Shapes - Sara Soueidan

Animating CSS Shapes with CSS Animations and Transitions - Sara Soueidan

Using CSS Regions With CSS Shapes For A Better Reading Experience - Sara Soueidan

Creating Non-Rectangular Layouts With CSS Shapes - Sara Soueidan

Take A New Look At CSS Shapes - Rachel Andrew

People Talkin’ Shapes - Chris Coyier

CSS Shape Editors - Chris Coyier

Experimental layouts with CSS Shapes and clip-path - Michelle Barker

Breaking Down Boxes with CSS Shapes - Amelia Bellamy-Royds

A Redesign with CSS Shapes - Eric Meyer

Why you should be excited about CSS shapes - Chen Hui Jing

An Introduction to CSS Shapes - Tania Rascia

Art Direction For The Web Using CSS Shapes - Andy Clarke

Videos:

Edit your CSS Shapes with the Shape Path Editor - Miriam Suzanne, Mozilla Developer

Obliterate Boxiness with CSS Shapes - Jen Simmons

The Firefox Shape Path Editor - Jen Simmons

Building a Richer Storytelling Experience with Alice in Wonderland - Adobe

8 Little Videos About the Firefox Shape Path Editor - Mikael Ainalem

Podcasts

Jen Simmons and Intrinsic Web Design - Shop Talk Show

Talk Slides:

Breaking the norm with creative CSS - Aga Naplocha

CSS Shapes & Friends - Nicky Thompson

Helpful Tools:

Shape Path Editor - MDN

Dynamic Drop Caps - Andy Barefoot

Can I use css shapes? - Caniuse

Examples:

CSS Shapes - Jen Simmons

CSS Shapes, Columns and Clipping - Mandy Michael

CSS Shapes Collection - Kristopher Van Sant

Demo for Alice's Adventures in Wonderland - Adobe

Inspiration:

shapes of text Pinterest board - Kristopher Van Sant