The first 5 are Tobianos. The last one... i think is an overo, possibly a tovero.
The website appylover listed are great. You can remember each by where the dark parts are (tobianos will have dark heads, legs, chests, flanks, etc)... but the way someone explained it to me once was: tobianos generally look like white horses with dark patches. Overos often look like dark horses with white patches (that are often splotchy). Or Overos from the side view look like they've been outlined in color with white in the middle of the horse. But these are just ideas and not rules. Sometimes some horses are kind of hard to tell!