Photoshop is the industry standard not only in raster graphics editing, but in digital art & design as a whole.
Canva is a freemium online graphics tool that’s extremely simple to use and offers a wide variety of templates.
Illustrator is an industry benchmark in vector tools and is perfect for corporate logos or website mockups.
Corel Draw packs some pro-level features and offers a highly accessible interface that is easy to use.
GIMP is much more than just a photo editor that offers a lot of incredible Photoshop features for free.