B-Side Comics

Webcomics will often have a separate series of strips featuring characters and/or situations outside of the main storyline. These may be used as Filler Strips, a form of Breather Episode, or just Something Completely Different.

Back in the Golden Age of Newspaper Comics, when Sunday comic strips each took up a whole page of the newspaper, they were often accompanied by "toppers", which served much the same purpose, making this Older Than Television.

The "topper" best remembered today is Krazy Kat, which originated as a set of strips under the main action in a 1910 strip known variously as The Dingbat Family and The Family Upstairs (making it a "bottomer", I suppose, though let's all agree never to use that term again). According to Don Markstein, Krazy spun off into his (or her) own strip in 1913, while the Dingbats passed from the comics page in 1916.

There are other famous newspaper "toppers" out there in comic history, and Your Obedient Serpent is going to wave his wand and invoke the Wiki Magic to transmogrify this entry into a more detailed examination of them.

See also Omake.

Comic Books

 * Watchmen had "Tales of the Black Freighter", which served to metaphorically comment on the main plot.

Web Comics

 * Sluggy Freelance has had such B-Side Comics as "Bikini Suicide Frisbee Days" (aka, back in the good old days before plot locked up the characters in specific situations) and "Meanwhile in the Dimension of Pain", drawn by guest artists. The latter actually ended up affecting the main story. It has also has an ongoing side story called "Stick Figures in Space", which is used as filler.
 * The Chef Brian, Players and Gamer's Glossary strips in Ctrl+Alt+Del.
 * In fact, Ctrl+Alt+Del often has a few gag comics between Story Arcs.
 * And now the "sillies" that are in a separate part of the site.
 * "Penny Arcade" has a few B-Side comics: "Twisp and Catsby" and "The Cardboard Tube Samurai" evolved from strips in the main continuity to their own identity. There was a series of three (link) treatments of B-Side comics with a poll to determine which gets developed more: "Lookouts", "Automata", and "Jim Darkmagic". It was popular enough that both "Lookouts" and "Automata" got additional strips.
 * Megatokyo does skits featuring the characters in different genres in between chapters, though this really falls under Omake.
 * Stickman and Cube has "The Adventures Of Captain Invisible" and "Cube's Past Jobs".
 * User Friendly has frequent strips involving caricatures of technology magnates and politicians (and Apple-obsessed aliens), which don't affect the main storylines.
 * Apple Geeks and its AG-lite.
 * El Goonish Shive has the newspaper-style comics found in EGS: NP; these are sometimes part of the main continuity and sometimes aren't. Regardless, they usually don't tie into the main plot, and are markedly drama-free.
 * "Megagamerz 733t" from Goats is completely unrelated to the story, save that it is ostensibly drawn by one of the characters, which may in fact lump it in with "Drawn by Billy" sets from The Family Circus.
 * The Genie World story from The Wotch.
 * Not to mention the arcs where someone takes over the "Wotch HQ" and attempts to run the comic his way.
 * Or "The Wotch: Cheer", an entire spinoff comic based around four of the early transgendered characters, in their new lives as cheerleaders.
 * Something*Positive has S*P 1937/8. One could also throw "New Gold Dreams" and "Midnight Macabre" into this mix.
 * Head Trip site has the adventures of Emo Kid and Chemo Kid, a Kid Hero team consisting of a Littlest Cancer Patient (also a Knight in Sour Armour) and an Emo Teen. Together, They Fight Crime!
 * SSDD has two: Sticky the Stickman and Church of Poisoned Minds, which eventually became their own strips.
 * Girl Genius has a series of radio plays done as podcasts, supposedly in the future but with no clear relation to the plot at present. One has been turned into actual comics.
 * There was also the Mary Sue spoof titled "Fan Fiction".
 * Scary-Go-Round had a brief story about two goblins setting up a detective agency, going to Ireland to recover a pot of gold from a goblin version of Terry Wogan, and mixing it with devil bears. While the goblins do make occasional appearances in the main SGR comic, usually around Christmas, apparently this storyline provoked a great many e-mails to John Allison saying, "I don't get it," and he now thinks he could just have done it with Shelley and Amy instead. It didn't stop him doing another goblins-in-Ireland story-ette a few years later.
 * VG Cats has two secondary comics, Adventure Log and Super Effective, an RPG "diary" and a Pokémon parody, respectively.
 * After Taña, Island Princess concluded its first volume, its creator started an unrelated story at Comic Genesis called "Get Your Boyfriend Back" (not transferred to Drunk Duck yet).
 * Sins Venials has DDG, updated every time Sins Venials' donation box reaches $50. DDG arguably has a stronger storyline than the main comic. View it here.
 * Ultima-Java: Creative Media has If You Believe, Over the Edge, World of Heroes, U-2 (the series before the Continuity Reboot) and more on the way. Over the Edge and World of Heroes have become Orphaned Series, however — the latter of which recently being moved to the site's forums.
 * Zap! has a side comic, Everybody Loves Robot, written and illustrated by the main comic's writer.
 * Triquetra Cats has its spinoff, Polonian Tales.
 * Early Adventurers! had several B-Side Comics. Some one-shots, some told an ongoing story.
 * Questionable Content is occasionally interrupted by 'Yelling Bird', four identical panels of an angry dickcissel, when the author is too busy or unwell to draw a regular strip.
 * ... which has since added characters and mutated into something resembling an actual storyline.
 * Sunday editions of Narbonic are usually some form of these, such as "The Astonishing Excursions of Helen Narbon & Co."
 * The Life of Nob T. Mouse used 'interlude' stories to break up the longer Pie Noon storyline into more manageable pieces. These included Doctor Nob, a parody of Doctor Who, and The Trouble With A Quantum Santa, which parodied the idea that Santa can deliver presents to the entire world in one night.
 * Acrobat will post pinups, origins of characters, or short stories in between issues.
 * DMFA has Abel's Story, a backstory for one of the characters.
 * A Modest Destiny used to alternate seasons of The Starship Destiny with the main comic. Presumably because new characters and a new setting (scifi as opposed to medieval adventure) gave Sean "Squidi" Howard a break and a chance to shake things up a bit.
 * Unwinder's Tall Comics were at one point interrupted by a Steampunk comic Apocalyptus: Thrift and Peril, which is completely unrelated to the main story. Also at least one character has her own comic on Drunk Duck.
 * Fall City Blues has "Transitfish Syndrome," in which the main characters engage in some surrealism, and "Fall City Blues (unframed!)" featuring random gags and filler strips.
 * Shortpacked features occasional digressions about the author's personal life (usually his trips to conventions), hastily drawn in blue pen and then inked over.
 * Fathead's Jeff has a recurring segment which is basically a parody of family sitcoms.