Brilliant, but Lazy: Invoked in the episode where the characters get their SAT scores back and Zack scores extremely high. The other characters realize out loud that although Zack's lazy, he's a lot smarter than he lets on. Zack himself tells them to keep it quiet, since he has "a reputation to look out for."
Informed Attractiveness: Kelly was hot, no doubt, but few would argue that Lisa or Jessie were not just as hot. Within canon, however, Kelly was treated like a supermodel parading through the school.
Ivy League For Everyone: Probably the worst offender; 1100 on her SAT and from a cash strapped family yet made it into the same prestigious (if fictional) university as Zach (high SAT/upper middle-class family), Screech (Valedictorian), and Slater (sports scholarship).
Military Brat: Somewhat inverted as even though her father, Frank worked at a defense plant, she never had to move around, unlike Slater.
Nice Girl: She's head cheerleader and the most popular girl in school but she's also the most sweet natured character in the show (and it isn't because she's spoiled sweet either because she's from a poor family).
Suspiciously Similar Substitute: Sort of. After Kelly and Jesse left the show, Lisa got a noticable boost in both popularity and brains so she could step into their shoes as the pretty one and the smart one to play against Tori's wild one. Lisa was always popular in canon, but after the other two left, it's like she became the only hot girl left at Bayside.
New Transfer Student: Technically. He transferred to Bayside at the very beginning of the series, so he's not any newer to the audience than the rest of the characters. However, to the characters on the show, he was "the new guy," and the first season kept emphasizing this.
Reasonable Authority Figure: Even Zack occasionally admits that Belding is a lot more reasonable than he usually gives him credit for. During the graduation episode, Zack gives Belding a hug. In the "Wedding in Vegas" movie when Belding is a guest at Zack and Kelly's wedding, Zack finally admits that he appreciates Mr. Belding and says "You made high school challenging."
Worthy Opponent: Despite his Butt Monkey status, he's one of the few people who can keep up with Zack's schemes and even turn them against him on a regular basis. Zack even admitted that that Mr. Belding made things challenging for him.
What Happened to the Mouse?: Kelly and Jessie disappear, Tori appears and takes their place for nine episodes, then disappears, Jessie and Kelly reappear and everything carries on as normal as if Tori never existed.
The Tori episodes were filmed after the series finale and the made-for-TV movie that were supposed to wrap up the plot of the series, but were inserted into the middle of the season, as their storylines take place at the high school, in the usual canon of the series. This has lead to a series of gigantic plot holes that fans call the "Tori Paradox": Out of nowhere, Jessie and Kelly unexplainably disappear; Tori starts as a new student at the school and instantly befriends the main cast, who are carrying on as if Jessie and Kelly never existed; She is established as some kind of hybrid of Jessie and Kelly, thus she is beautiful and athletic while being smart, snarky and feminist; Zack begins a romantic relationship with her with absolutely no mention of his relationship with Kelly and showing no remorse for the fact that he is potentially cheating on her with Tori; Zack and Tori break up and all of a sudden, she is gone with no explanation of her fate; Jessie and Kelly reappear and everything reverts back to how it was before Tori appeared, Zack and Kelly get engaged and everyone graduates with no mention of Tori whatsoever, as if she was never there in the first place. Promotional cast pictures exist that feature both Tori and Kelly (together at the same time) with all of the actors wearing college sweatshirts hinting that Tori was, at one point, being considered to appear in The College Years.
Glory Days: A former NFL player for the San Francisco 49'ers, Mike often wistfully reminisces about his days as a football player, and clearly loves the sport. On one occasion, while complaining about a Jerkass from his old team, he admits that he's jealous, and says "He's getting paid millions to play a game that I would have been willing to play for free."
Landlord: OK, not actually a landlord, as the characters were living in a college dorm, but he was their Resident Advisor, so Landlord is probably the closest trope that fits.
Renaissance Man: Is in the glee club, is a science geek, and mentions taking a Spanish cooking class.
Jerk Jock sometimes. By the end though, he, Screech, and Big Pete have a "breakthrough" during Mr. Belding's bizarre group-psychotherapy session in gym class, and Ox ends up swearing off making fun of nerds again.