Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Placid - Use Placid to auto-generate images, videos & PDFs from reusable templates
Sketch - Professional digital design for Mac.
Robolly - Auto‑personalize your open graph, social posts & more
Affinity Designer - Professional creative software, exclusively for Mac.
OG IMPACT - A free, open source API for generating social media images