This is not a complete list of every type of abrasive blasting media out there, just a quick run down of the more popular ones.
Fused Aluminum Oxide (Brown) is considered and industry standard. It's meticulously shaped to be sharp so it's great for cutting through burrs, mill scale paint, or rust. Given the time, it'll cut through steel. It's highly resuseable because of it's slow breakdown rate. In addition because there's virtually no iron in aluminum oxide it's ideal for stainless steel.
Fused Aluminum Oxide (White) is made much the same way as it's counterpart however it's harder, sharper and cuts better it's draw back is that it's brittle and it's breakdown rate is higher. Plus it's more expensive and because you'll be buying it more often, makes it a more costly option.
Glass Impact Beads may sound menacing but it's actually one of the safest sandblasting medias for workers and the enviroment because it contains 0% silica. Glass bead is considered a cleaning or scrubbing media because of it's circular or 'no profile' surface. It scrubs down high spots on metal leaving it more polished looking than sand blasted.
Crushed Glass really has a lot in common with glass beads in that it's chemically inert completely free of silica and leaves a similar finish. In addition to that it's 100% recycled glass, and has a good break down rate so it can be reused many times over.
Plastic Media is an sort of uncommon media in our industry but widely used in aerospace where it's relative softness is prefered, because it doesn't damage the aircrafts aluminum alloy framework. There are a few different types of this media including melamine and acrylic. And it all depends on what you'll be using it for.
Steel Grit & Steel Shot are naturally very hard, highly reuseable and very aggresive medias widely used on railcars and foundries where slag and serious rust and multiple layers of paint are common. It can also be used in airless wheel blast machines for surface polishing as well as some peening applications.
Crushed Walnut leaves behind a clean finish without marring our damaging the base metal. Of course it's enviromentally friendly and renewable and has a . It can be used to deflash plastic parts and debur metal parts as well as strip paint quite well.