The next set of tools, all within their own box, are tools that use brushes of various sizes. We will only look at 3 today, but you can experiment with the others later. Just like it sounds. You can also hold the shift key to make a straight line between points. Also uses brushes.
Any pixel touched by the eraser is removed and set to transparent.
You can get a similar effect using a paintbrush and white, but that leaves the pixels white and opaque. Background eraser allows you to just erase some areas and leave others alone. Magic Eraser works like the Magic Wand. Line allows you to drag a line onto your image. Settings in between will fill touching pixels whose color is within tolerance.