Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.
Phigma - 100+ Figma templates for your Product Hunt images
Invision - Prototyping and collaboration for design teams
Zeplin - Collaboration app for UI designers & frontend developers
Figma 101 by Designlab - Learn Figma in this free course w/ downloadable templates
ProtoPie - ProtoPie is the easiest tool used to turn your UI/UX design ideas into highly interactive prototypes for mobile, desktop, web, all the way to IoT.