I made the rest of the Billiard Balls from 1-Ball to 21-Ball! No, these are NOT based off of a certain somebody's characters. 1-Ball: He's the leader of the Billiard Ball crew. He's kind of bossy and rude. 2-Ball: They are 1-Ball's partner-in-crime. 3-Ball: She's loyal to anybody. 4-Ball: She mostly can't make up her mind. 5-Ball: He is interested in a lot of things. 6-Ball: She's kind of a 10-Ball clone, except she is obsessed with the letter E instead of the number 10. 7-Ball: He is pretty much self-centric. He brags about his luck. 9-Ball: You already know a bit about them, watch TPOT. 11-Ball: He is very grumpy. 12-Ball is the reason for this. However, he does have a good side. 12-Ball: She's annoying. She likes to annoy 11-Ball to the point where he pushes her away. 13-Ball: They try to be involved in things, but their voice is never heard (I mean nobody listens to them). 14-Ball: 7-Ball's egotistical sister. 15-Ball: They just agree with everybody else. 16-Ball: She doesn't like conflicts or drama. 17-Ball: They are often bossed around by 1-Ball. 18-Ball: He is very friendly. 19-Ball: She's super enthusiastic. 20-Ball: She likes to make jokes. Sometimes, her jokes can be a bit annoying, but not as annoying as 12-Ball's entire personality. 21-Ball: He's kind of dimwitted. (Scroll down for spoilers) They all play a major role in 10-Ball's backstory.
Credit 2 Every1, especially Jacknjellify for BFDI.