Trace by Sticker Mule - Remove the background from any image for free
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
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
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.