The past 20 years or so have seen a surge in the popularity of evil, Joker-style Monster Clowns who deliberately and very effectively invert everything clowns were traditionally assumed to represent - that is, making people laugh, especially children. However, there was a time when clowns were treated in the popular media as sympathetic figures of whimsy and silly fun. Pretty much the only clown left in the public eye who is still permitted to act at all clown-like is Ronald McDonald. (And now that he's being phased out of the advertising, we don't even have him anymore.) But in days past...
For clarification, it should be noted that a degree of irony is intrinsic to most clown performances, and indeed to humor in general. The traditional "tears" painted on a clown's cheeks are there to show that he is laughing on the outside but may be crying on the inside, an acknowledgment by the performer that most humor contains at least some element of laughing at another's pain. This is most played up in old-school, down-on-their-luck "hobo" clowns like Emmett Kelly Jr., though the ultimate artistic expression of the tragic clown concept is probably the title aria in the opera Pagliacci. The "Non-Ironic" in the trope's name simply refers to the clowns listed here not being evil or deliberately frightening.
See The Jester for a more common type.
Jack Box is an unusual variant, since his head resembles a simplistic Jack-in-the-Box toy. His personality in newer ads isn't clownish at all, but rather that of a slightly unorthodox yet very effective businessman.
Krinkles the Clown from the long-discontinued Sugar Krinkles cereal. He's supposed to be a happy and cheerful clown, but...
Comic Books
Batman #528 has yet another tragic, "life's loser" clown that works at a barely-surviving circus. He manages to disrupt the Mexican Standoff between Batman, Two-Face, and the circus' corrupt owner by releasing a lion from its cage, and later informs Batman that he had seen said owner murder his uncle, the circus' previous owner, by loosing a tiger on him. His reason for not revealing this to the cops? He feared that the circus would be shut down, and since he has no savings and few job skills... After reflecting on this for the better part of a few years, however, and getting a chewing-out from the Dark Knight, he decides to go and testify to the cops after all. (For extra irony points, the case was one of the many "ghost files" that Two-Face possessed back when he was still District Attorney - he knew who was responsible, but couldn't prosecute as he had no evidence).
Phroso the clown in Freaks is a textbook example — works hard on new gags for his act, a friend to all the sideshow folk, kind to the pinheads, develops a truly sweet romance with an animal trainer — really a heck of a guy.
Harpo Marx's persona had most of the characteristics of a clown, if not the face paint.
Charlie Chaplin's The Circus, featuring Chaplin stock player Henry Bergman as an entirely non-ironic clown.
Bozo, the "World's Most Famous Clown," had the distinction of being portrayed both by a live actor and as a cartoon on his television program.
Red Skelton's most famous character, Clem Kadiddlehopper.
Or, more obviously, Freddie the Freeloader.
Or, even more accurately, Red, himself, was the clown, able to take on may persona - Mean Wittle Kid, Clem, Freddie, Gertrude and Heathcliff, and on and on.
Russian kids' green screen show Komedya Klowna (??????? K?????) (mostly) features these.
JP Patches, who to this day, decades after his show was cancelled, he still performs as his clown character.
Barnaby, an English sheepdog in a bowler hat and baggy pants who regularly performed on Disney's Dumbo's Circus. He was shown to be friendly if kind of stupid, and he was actually more of a jack-of-all-trades than a clown, also performing magic and the like.
Theater
The tragic clown opera Pagliacci (although it must be said that, even if nobody in it is a modern "monster clown" psycho, none of them are nice people).
Cirque du Soleil, as noted under the Real Life listing, uses lots of these — and Corteo is actually about them; most of the major characters are turn-of-the-20th-century circus clowns. A stated goal of this show was to present funny and lovable clowns to audiences, especially children, who may never have seen them as such.
The fact that he tells horrible jokes doesn't help, although his determination to restore the circus, and teach Regina the truth about death, restores his worth in a lot of fans eyes.
The Sims: The clown who hassles your Sims is a nuisance, but he's not particularly evil. He's just bad at his job.
Hitman: Blood Money has a clown at a kid's birthday party whose clothes you can steal. The protagonist, 47, even once won a 'Clown of the Year' award. Of course, given the nature of the game, you may end up a Monster Clown instead.
Dark Cloud 2 goes both ways. While you do spend the early portions of the game fighting an evil clown and his circus troupe....
you can also unlock a clown outfit for the male protagonist, build clown themed parts for his Ridepod, and be greeted a perfectly friendly jester fond of hiding in dungeon treasure chests. He might even hook you up with above average loot!
Web Original
Atop the Fourth Wall: Sick of the proliferation of Monster Clown characters, Linkara created Boffo the Clown to be a recurring character. Unfortunatly for him, he was created at the beginning of The Entity's arc and as such promptly was kidnapped by The Entity. He returned at the end of the arc. He's also Linkara's accountant!
Western Animation
The Powerpuff Girls has Rainbow the Clown, who is this except for the one time he was temporarily turned into an Enemy Mime. The girls still beat him up and toss him into jail after he turns back though.
In a later episode he appears at the Powerpuff Girls' birthday party, so it seems he's back into freedom and as cheery as ever.
The Jerry Lewis-esque clown in the Animaniacs episode "Clown and Out." (Certain of the characters view him as a Monster Clown, however, as they have "clownophobia."*
The actual word for an irrational fear of clowns is "coulrophobia".
Krusty is a cynical parody of this (more specifically, Bozo), yet despite his being greedy and disinterested, his merchandise being low-quality and dangerous and his show's shrinking budget, he manages to bring joy to children and we occasionally see hints that even after everything, he still loves comedy. Even if he is a hack.
Binky the Clown is another parody. Unlike Krusty, he's passionate about being a clown; he's just obnoxious. Played far straighter in the comics, where Garfield genuinely enjoys Binky's antics. That is, when he isn't the target of Binky's antics.
Max Fleischer's Koko the Clown, one of the earliest cartoon characters.
Real Life
Emmet Kelly, Jr.
Sad clowns in general usually avoid the Monster Clown treatment, since a painted-on smile is what tends to freak people out the most.
Any traditional circus clowns, be they part of Ringling Bros., Cirque du Soleil, or other troupes.
While the mere fact that they are ball-jointed dolls might push them into Creepy Doll territory for most people, the Iplehouse Tania Pierrot is seemingly clown-themed and played for Rule of Cute.
