Loops Feedback - Feedback on design ideas in minutes via 110m+ people
Usersnap - Visual Feedback - Usersnap helps your business with its versatile feedback platform to build better, more successful products and services with the help of user feedback. Collect feedback along your product development lifecycle. Try it for free.
Marker.io for Slack - Turn screenshots into Slack messages ✌️
Feedback by Pixelic - Painless design feedback and version control.
Planogy - A feedback platform for all the creative work
Sesov - A community for anonymous design feedback