PhotoFlare - Quick, simple but powerful Cross Platform image editor.
Trace by Sticker Mule - Remove the background from any image for free
showFoto - ShowFoto is the standalone image editor of the digiKam project.
PhotoRoom - Create studio-quality product pictures in seconds.
PhotoDemon - Lightweight portable BSD licensed photo editor for Windows focused on performance and usability.
Icons8 Background Remover - Quickly remove the background from any photo