Nice Guy: Romeo is implied to be this, considering the fact that Lord Capulet doesn't actually care when he's told that Romeo is at his party and says he's heard nice things about the boy. Keep in mind, this is the guy that was trying to kill said boy's father less than 24 hours earlier for no other reason than some old rivalry that no one remembers the cause of.
Serial Romeo: His object of hopeless affection changes on a dime in the play, and it's implied he's done this sort of thing before. He knew Juliet for about a minute, and was already making out with her.
Women Are Wiser: Juliet is way more practical and level-headed than Romeo. She's the one who proposes they get married, and worries about Romeo being caught by her kinsmen when he's climbed up to her balcony.
Informed Attribute: Mercutio describes Benvolio as Hot-Blooded, willing to start a fight for any reason at all. In practice, Benvolio is a level-headed Nice Guy, and Mercutio's description of Benvolio is more applicable to himself.
Deadpan Snarker: To the point that audiences (despite typically knowing fate from high school literature) will sometimes take a while to get that he's not kidding after being stabbed by Tybalt.
Forgotten Fallen Friend: Romeo is heartbroken about Mercutio's death... at least during the scene where Mercutio actually died. After Romeo kills Tybalt to avenge him, Mercutio is pretty much forgotten. Romeo expresses far more grief over Tybalt's death than Mercutio's.
In fairness, that's likely because Romeo himself killed Tybalt (Juliet's cousin) and he feels guilt over that.
What the Hell, Hero?: To Romeo, twice. First, he calls him out for falling for a girl he met a day ago while completely forgetting about Rose. Secondly, he calls out Romeo for his excessive Wangst and tells him to suck it up and go do something about it.
Anti-Villain: Depending on your view, Paris could count as a Type IV. He's Romeo's rival for Juliet's hand, but is a good man who would have made a good husband for Juliet... Just the right guy, but in the wrong moment and place.
Meaningful Name: In a manner of speaking. "Paris" was a common name in Shakespeare's day for a plant also called "truelove", and it's very likely that he intended to show that, tragically, Juliet may have actually come to experience a fulfilling, life-long romance with Paris had she ended up with him.
Nice Guy: Although how nice he is depends on the staging.
Adaptation Expansion: In the Presgurvic musical, she's a widow (running the Montague family on her own and frustrated by her inability to stop her family from battling the Capulets), and she survives the end of the play.
Demoted to Extra: Double Subverted. For the character whose failure to do a simple job drives the ultimate tragedy of the story, he has a grand total of four lines in the original work. But dang, are those four lines important.
Nice Job Breaking It, Hero: Because he stopped to get some company for the trip delivering Friar Lawrence's letter, he was locked up for fear of contracting the plague, and wasn't able to deliver the letter explaining that Juliet was alive to Romeo.