Crabbe & Goyle
Crabbe and Goyle are Draco Malfoy's two best friends at Hogwarts, who follow him everywhere and don't really offer much else. Both in Slytherin, they often serve to simply back up Draco, laughing at his jokes and doing whatever he tells them. They are often described as ‘large and thuggish’, and aren't known for being very smart... Without Malfoy as their leader, who knows what this pair would end up doing.
There truly might not be an interesting thing to say about Crabbe & Goyle. They seem to exist to just follow Malfoy around.