GIMP - GIMP is a multiplatform photo manipulation tool.
Polarr - MacOS, Windows, iOS, Android and online photo editing tools & free photo editors.
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
Doka.js - High-performance JavaScript image editing in the browser ✂️
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
Dark Room - A quick, powerful photo editor that gives you control