Majestic - Majestic - Link intelligence tools for SEO and Internet PR and Marketing. Site Explorer shows inbound link and site summary data.
Invision - Prototyping and collaboration for design teams
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.
Zeplin - Collaboration app for UI designers & frontend developers
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.