Whilst Rachel, Monica, Phoebe, Joey, Ross and Chandler proved more than capable of keeping us entertained for a full 10 years, a large part of what made Friends such a fantastic show was its range of brilliant fringe characters. These were often family members, romantic partners, work colleagues or other friends, many of whom appeared sporadically throughout the show, while others appeared in just a few episodes. These fringe characters were used expertly in Friends to keep things fresh and inject humor into the show to help drive the plot forwards. Here are 12 of the best.

12. Steve

Used in just two episodes, Steve (Jon Lovitz) ends up stealing the show. He first appeared in “The One with the Stoned Guy” in season one, where he plays the title character who is a restaurateur looking for a new chef. Phoebe recommends Monica, who then prepares a gourmet meal for him at her apartment. Phoebe reveals that he smoked a joint on the way, and it soon becomes apparent that he is high as a kite. Instead of waiting for the meal, he is far more interested in taco shells and gummy bears. Steve does not reappear till “The One with the Blind Dates” in season nine, but it is another hilarious appearance where he is on a blind date with Rachel. The date is a complete nightmare, which sees Steve constantly insult himself, claim that he is infertile and begin to cry.

11. Ugly Naked Guy

Although frequently referred to throughout the show, Ugly Naked Guy (fortunately) is only partly visible twice during the 10 seasons. Despite this, he is an important character. Living opposite Monica and Rachel, Ugly Naked Guy is constantly naked and always has the drapes open. A running gag is the gang commenting on the strange activity that he is doing, which has included playing the cello and wearing gravity boots. He has been a key element in the plot of two episodes, with the first being where the gang construct a giant poking device after they fear that he has died. The second is where Ross wants to move into his apartment, seeing him attempt to befriend Ugly Naked Guy—“Check it out! Ugly Naked Guy has a naked friend!” The gang all at the window watching Ugly Naked Guy became an iconic image and often united them as a group.

10. Estelle Leonard

Estelle is Joey’s chain-smoking agent who can provide plenty of humor on the show. In addition to her chain-smoking, voice and striking appearance, she has a comical relationship with Joey where, for the most part, she is unable to find him any work (although she did get him his breakout role as Dr. Drake Ramoray). She even attempted to sabotage his career at one point when she thought he had left her, but he was still her client. She passed away in the final season, seeing Phoebe impersonate her on the phone as she feared for how Joey would take the news. She does this once after Joey finds out, seeing him believe he had received a message from beyond the grave. At the time of her death, her only clients were Joey and Al Zebooker, a man who eats paper (who does this at the funeral).

9. Mr. Heckles

The strange elderly neighbor always in a dressing gown, Mr. Heckles appears sporadically throughout the show and is always used to great effect. Living below Monica and Rachel, he is usually seen complaining about apparent noise, and he will either show up at their apartment to complain or hit his apartment ceiling with a broom. He is known as a compulsive liar, however, and has complained that they were disrupting his birds, obo playing and a dinner party. He also claimed to own Paulo’s cat, and lied about being Chandler’s new roommate to Eddie (more on him to come) and waltzed into Chandler’s apartment. His death causes Chandler to examine his own life, as after looking through Mr. Heckles’ belongings he draws parallels between their lives. This frightens Chandler, seeing him attempt to stop being so selective and get over his fear of commitment.

8. Eddie

Although Eddie appears in just three episodes, his wild and unpredictable nature makes him one of the more memorable characters. When Joey moves out, Chandler is on the hunt for a roommate. He settles on Eddie (Adam Goldberg), but quickly realizes that they have nothing in common, as Eddie doesn’t like sports, foosball or Baywatch. It becomes apparent that this is not the only issue, as Eddie is completely insane. He accuses Chandler of sleeping with his ex-girlfriend and killing his fish, which he later replaces with a Goldfish cracker named Chandler. He also steals Chandler’s insoles and watches him sleep. This makes him suspect that Eddie is mentally ill, which is confirmed after Eddie forgets that Chandler asked him to move out and he instead believes that they went to Las Vegas. Chandler then uses this against Eddie by convincing him that he had never moved in at all.

7. Mike Hannigan

Played by Paul Rudd, Mike is Phoebe’s love interest and eventual husband. This makes him a key character towards the end of the show and he becomes a part of the gang, but he is also introduced in brilliant fashion. After Phoebe and Joey agree to set each other up with dates, Joey forgets to find anyone but tells Phoebe that he is setting her up with an old friend called Mike. He then visits Central Perk where he shouts out the name Mike, causing the two to meet before a hilarious double date which fails miserably. Mike is musical and also quite quirky, and seems to be the perfect fit for Phoebe, keeping her somewhat grounded. After she changes her name to Princess Consuela Bananahammock, he convinces her to change it back after claiming that he, too, would change his name, to “Crap Bag.”

6. Frank Buffay, Jr.

Brilliantly portrayed by Giovanni Ribisi, Frank Buffay Jr. is Phoebe’s idiotic younger half-brother. They do not meet until he is an adolescent, and he becomes a key character on the show in the third season where he starts dating his home economics teacher, Alice (Debra Jo Rupp). They form one of the more memorable relationships on the show, with Alice being 26 years older and Frank often calling her “Ms. Knight.” Although Phoebe is initially disgusted by their relationship, she cannot stop them and they get married before asking her to carry their child. She ends up delivering triplets named Frank Jr. Jr., Leslie and Chandler (a girl). Frank reappears much later in the show and is struggling with looking after three kids, claiming he hasn’t slept “in four years.” He also once thought that a massage parlor was a brothel, seeing him believe that Phoebe was a prostitute.

5. Gunther

Appearing in 185 episodes, Gunther (James Michael Tyler) is the character with the most appearances after the main cast. He is the manager of Central Perk, a location in which the group spends an enormous amount of time together. They therefore have many fantastic interactions with him over the course of the 10 seasons, and a running joke throughout is his love for Rachel, as well as his inability to penetrate the inner circle. Despite this, they consider him a friend and he is invited to informal parties (but not events such as weddings). He provides plenty of light humor over the course of the series and features heavily in some episodes, which usually sees him do anything for Rachel. Also, due to his love for Rachel, he is often shown to dislike Ross and was the one who told her about Ross’s one night stand.

4. Richard Burke

Close friends with Monica and Ross’s parents, Richard Burke is an ophthalmologist who all the women swoon for. Played by Tom Selleck, he is mustached, smokes cigars, intelligent, funny and considered to be the pinnacle of manliness. He and Monica begin a relationship despite the age gap of 21 years, and Monica falls deeply in love with him. Comically, Joey and Chandler are also won over by Richard, seeing Joey begin smoking cigars and Chandler grow a mustache. Due to Richard not wanting kids, they break up but both are devastated. He reappears later in the show when Monica is with Chandler, which makes Chandler very insecure as he knows how in love Monica was with him, and he also feels inferior to the manly Richard. Integral to the story, he was also comical and helped to develop the characters of Monica and Chandler.

3. David

Brilliantly played by Hank Azaria, David is Phoebe’s first serious love interest and thought to be the love of her life. Also known as “David the Scientist Guy,” he is a physicist with large round spectacles, and he often stutters and is unsure of himself. This all makes him a likeable and sympathetic character, but his relationship with Phoebe ends when he has to go to Minsk for work. He returns for an episode in season seven, and again in the second half of season nine after failing his research in Minsk. He professes his love for Phoebe, but by this point she has moved on to Mike and accepts his marriage proposal, at the same time that David himself is trying to propose. Although it is a sad ending for David, his passion for his work ultimately doomed their relationship and Mike proved to be the perfect fit for Phoebe.

2. Jack Geller

Father to Monica and Ross and husband to Judy, Jack Geller (Elliott Gould) brilliantly plays the role of the embarrassing father. He frequently makes ill-timed and inappropriate comments and reveals too much information, but despite this he is a good parent who loves his kids. He and Judy are often used to reveal more information about Ross and Monica’s past, and they feature in all episodes with a big event such as weddings, birthdays and Thanksgiving. In addition to the humor with his children, Jack also has a comical relationship with Chandler. Chandler tries desperately to impress and win over his girlfriend’s father, and after a few bumps on the road he eventually does so after standing by Ross through his apparent “drug problems” and for then taking on Monica as well. After fearing he is too predictable, Jack claims that he wishes to be buried at sea.

1. Janice

“OH. MY. GOD.” is perhaps the most famous Friends quote, and it was frequently delivered by the fantastic character of Janice, along with her trademark laugh. Chandler’s on-again, off-again girlfriend, Janice has an obnoxious and nasally voice which is the source of much humor on the show, and she is often mocked by the other characters. Chandler always turns to her in moments of weakness, and she also bumps into Chandler at important moments, including on a blind date, at the sperm bank, whilst Rachel is in labor and, finally, at the house next door to the one he and Monica are going to buy. She is crucial in Chandler’s character arc (the biggest on the show), and she is also the funniest fringe character. Although everyone finds her insufferable, she also briefly dates Ross before freaking out Joey by stating “I guess that’s two out of three, Joey.”