Sanding is done to smoothen your wood. You can sand with different grains. lower grain means rougher sanding, higher grain means smoother sanding.
This one is practical in that you don’t use sanding paper, but when it wears off, you have to throw it away. Good to use wet as well.
The sanding block is used to wrap sanding paper around, and then applying it to your wood.
The detail sander has a smaller surface but has angled corners so it can reach corners of your products more easily. For larger surfaces it’s better to use a larger sander, orbital or belt.
The Orbit(al) Sander gets its name from the circular motion in which the sanding surface moves. It doesn’t rotate, rather it makes small circular motions
A variant on the Orbital Sander is the Random Orbital Sander, which moves in a more random way, such that you won’t get circular scratches on your work when you aren’t moving the sander all the time.
Nowadays, most Orbit sanders you can buy are random orbit sanders, because they are just better.
Orbit sander: Round sanding surface
Orbit sander: Square sanding surface
Larger surface, and better with corners.
This is the heavy duty hand saner of the bunch. More sanding, more fast. Not a detail sander though!
The edge sander is a table top sander. It’s position is static and you move your wood along its sanding belt.
. . . and there are more types of sanders. If you want, just browse on Amazon for some ideas: