Invision - Prototyping and collaboration for design teams
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.
Adobe XD - Adobe XD is an all-in-one UX/UI solution for designing websites, mobile apps and more.
Axure RP - The prototyping and specification software used by 87% of the Fortune 100. Beyond mockups, design interactive prototypes for business solutions, websites, and applications.
Pencil - Pencil is an animation/drawing software for Mac OS X, Windows, and Linux.