ClippingMagic.com - Remove image backgrounds online. Make backgrounds transparent, white, etc. Edit, crop, rotate, fix colors, add shadows, all you need for great photos!
GIMP - GIMP is a multiplatform photo manipulation tool.
Icons8 Background Remover - Quickly remove the background from any photo
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
Trace by Sticker Mule - Remove the background from any image for free
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.