Lucidchart is a web-based application to draw diagrams.

InVision is a prototyping, collaboration & workflow platform.

UXPin is a collaborative design platform, allowing entire teams to participate in the design process from start to finish.

Fluid UI is a browser-based wireframing and prototyping tool developed by Fluid Software and used to design mobile touch interfaces.

Mockup Designer is an online mockup creator.

Avocode helps you share design files, discuss changes, and code websites, mobile apps and newsletters faster.

Moqups is a streamlined and intuitive web app that helps you create and collaborate on wireframes, mockups, diagrams and prototypes for any type of project.

Concept.ly is the Web and Mobile mockups tool. Convert wireframes and designs into interactive Apps.

RealtimeBoard is an online whiteboard created as a team collaboration and brainstorming tool for agile teams.

Storyboard That is a free online storyboard creator.

Pidoco is a cloud-based collaboration software.