Landscape by Sprout Social - An interactive tool for social media image resizing
OG IMPACT - A free, open source API for generating social media images
Stencil - Stencil is a the fastest and simplest way to design images and graphics for digital marketing.
Robolly - Auto‑personalize your open graph, social posts & more
Social Share Preview - Check social media link previews while you browse
Social Image Generator - Automatically Generate Social Images For Your WordPress Site