Ok, since i've watched too much of Tremors, I know alot about these guys here.
Graboids are the main problem of the ppl of Perfection (Once known as Rejection) and the only way they hunt is by sound. They were named by Walter Chang - who got killed in the first movie. His great grandpa, Pyong Lien Chang called them Dirt dragons- They're in all 4 movies
A shrieker is what a graboid can turn into (it's sortta like ALIEN because it looks like a chest burster-like situation) They're deaf, so they hunt by using infrared. So it can see body heat (sortta like the Predator) they're in the second and third movies... plus the TV series
Ass blasters are what the Shriekers turn into. They shoot fire out of their @$$'s when they take off, then they fly around. They were named by Jodi Chang. Also, they - like Shriekers- see by infrared, but unlike the shriekers, they can hear aswell. Apparently, one lived at the end of the 3rd movie only to be sold to Siegfried and Roy. His name's Messerschmitt.
El Blanco is the albino Graboid. He kept chasing Burt gummer only because of the watch. Since he's an albino, he can't become a shrieker. Also, when he has enough food, he's full for a few days.
That's all i know about these guys
EDIT!!* someone noticed that i left out some other info. Ty for reminding me
The graboid's tounges look like weird mutated snakes. and when they grab you, they pull you into their mouths.
When a Shrieker eats too much, they have kids (it almost looks like their losing their lunch or something) AND they'll eat whatever tastes good to them... ANYTHING!
AND finally, when an ass blaster eats too much, they pass out and go into a coma