Full free mockup and product planning tool inside a browser extension
https://builder.io
Brad Czerniak (ao5357)
Dalimil Hajek
https://shotmockr.com
https://moqups.com/
http://anilk.strikingly.com/
https://screenshot.rocks
misterhamm
suziwen1
Screely
Somnath Nabajja (UX Designer)
Rodrigo Pombo