Here is a collection of tools that we find useful for developers and designers alike, please feel free to peruse the list and contact us if you recommend any.
Free tool for testing how good your website is, and what you can do to improve it. Check accessibility, SEO, social media, compliance and more. They score your website against other users/sites and provide badges to certain criteria.
Analyze and optimize your website with PageSpeed tools to implement the web performance best practices.
Before final completion of a website, it has to at least go through a green seal of approval from W3C.
Those cool icons on your site browsers. Just provide a 32x32+ PNG file and it will convert the file to an .ICO file.
An awesome responsive framework that allows flexible development of sites for desktop, tablets, and mobile.
Awesome grid "guide" for designers. They provide multiple file formats (PSD, AI ...) that follows a 960px grid rule. Something we use when creating new site designs.