Website Grader - Grade your website's strengths and weaknesses in seconds.
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Checkbot - Checkbot will boost the SEO, speed and security of your site by checking you're following 50+ web best practices. Browser extension with free and paid plans.
Invision - Prototyping and collaboration for design teams
PageSpeed Ninja - One-click page speed boost for WordPress
Sketch - Professional digital design for Mac.