Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
GEES - GEES is an all-in-one AI design platform that is shaping a future where you can brainstorm, design, hand-off in one file — without changing any other tools.
DragPotrace - A GUI for potrace using Objective-C for OS X 10.11
Sketch - Professional digital design for Mac.
Autotracer.org - Free online image vectorizer