Three other minor characters in addition to Feste have names that are clues to their personalities. One is Sir Tony Belch: the belch in his last name reflects the fact that he is constantly drinking. His name, in general, shows his love of a good time.
Another character with a descriptive name is Sir Andrew Aguecheek. Ague means shaking or shivering, and Sir Andrew's last name reflects the fact that, though a knight, he is a coward. It is a ridiculous name that matches this buffoonish character, who is a source of broad humor in the play.
Malvolio's name, which means malevolent, or filled with ill will, also matches his personality. He is a servant who is humorless and uptight, but becomes ridiculous when he is misled into thinking he might be able marry Lady Olivia. Olivia's maid, Maria, sets up this ruse by giving Malvolio a letter supposedly written by Olivia that says she loves him. In it, "Olivia" wishes he would smile more, act more pompous (contradictory to the first demand) and wear "cross-gartered yellow stocking." Such stockings are usually depicted in staged versions of the play as vivid yellow and crisscrossed with black strings or ribbons. In this ridiculous guise, Malvolio gets his comeuppance when, rather than impressed with behavior, Lady Olivia thinks he is insane and has him locked up in a dark room. Malvolio's fate illustrates the Renaissance idea that people shouldn't try to get above their born rank in life.
Shakespeare gave these characters such colorful names to signal to his audience that they are comic characters, included in the play because of their potential to draw laughs. Their names indicate their function as comic relief, but also are part of the broader zany quality of this play, which celebrates a holiday particularly tied to crazy antics.