Most companies will develop a series of design rules for their branding, logos, icons to help provide structure and clarity. These rules are known style guides or branding guides.

Adele
The repository of publicly available design systems and pattern libraries

Here are some examples that you might find useful if you are looking for inspiration.

Ubuntu
linux ubuntu style guide homepage

Yelp Style Guide
yelp website style guide design

Lonely Planet
lonely planet website design elements

Mapbox
mapbox style guide website layout

Salesforce
salesforce heroku app style guide

MailChimp UX

mailchimp ux patterns design website

WooThemes
woothemes wordpress themes style guide

Dropbox
dropbox style guide website

Clearleft
clearleft style guide website design
IBM Design Language
ibm design language website

Buffer App
buffer app style guide

BBC Style Guide
bbc style guide website layout

GitHub Styles

 

FontShop
fontshop style guide website colors

WordPress Branding
wordpress logo branding page design

DoSomething Pattern Library
dosomething pattern library website layout

Best Buy Brand Identity
bby best buy branding

Material Design
google material design style guide

Max Quattromani

 

Bourbon Patterns
bourbon refills patterns styles

South Tees Hospital
south tees hospital style guide website

Tuts+ Writing Guide
tutsplus style guide writing copy

Foundation Style Guide
zurb foundation style guide

Sky Global
sky global website style guide

Original author / source: Web Design Ledger