Modular Franchise

Sometimes a creator or company will strike gold. A work (film, novel, etc) may spawn sequels, adaptations to other media, and a bonanza of merchandise. Usually, it'll take place in its own distinct universe, the author having significant autonomy, or the time and place keeping it off limit for crossovers, like Star Wars, Lord of the Rings or Harry Potter.

However, sometimes the creator or company will try to replicate its own success, and come up with creations in similar genres. The similarities are noted and sooner or later the separate creations wind up crossing over with each other--either to pool resources that are individually flagging in interest, or just to enjoy the benefits of a Crossover. This new Shared Universe is a pretty perfect fit, and eventually it's seen as one giant franchise. However, at some point they may want to reboot only one piece of their mega-franchise, or adapt the simplest, most distilled aspect as it was originally envisioned. Luckily, these properties started out as their own franchise, so they can certainly stand on their own. But what you have is a modular franchise--full of properties that can be self-sustaining on their own, but also easily and even organically marketed as a unit.

Similar to Canon Welding, except usually done at a corporate level, and The Merch plays a much bigger role, if not the entire incentive.

See also Massive Multiplayer Crossover.

Comic Books

 * Superman and Batman are individually massive cultural icons. They're also members of the Justice League, which consists of all of DC Comic's other major superheroes--including ones like Wonder Woman who are popular in their own right. So you may see these characters playing out individually, or as a combo of the company's entire superhero line.
 * Marvel's a little more complex. They will often place things under the "Marvel Super-Heroes" banner. But unlike DC's stable, they don't always play well together, and many of their most popular characters aren't even major players in the company's Justice League analogue, The Avengers. Thus, for the purposes of editors, movie franchises or toys, they may divide the Marvel Universe into different "corners", with Spider-Man and the X-Men most often being their own distinct franchises. However, this may be changing, with both Spidey and Wolverine now included as Avenger members.

Film

 * Beginning with Frankenstein Meets the Wolf Man, Universal Pictures started pitting many of their monsters against each other, to the point they formed, for the most part, one cohesive universe with most of the action taking place in Eastern Germany. For years after, on things like video collections, cartoons and even postage stamps would sport a Universal Monsters logo featuring Dracula, Frankstein's Monster and its bride, the Mummy, the Wolf Man, and the Creature from the Black Lagoon. In 1999, Stephen Sommers remade The Mummy 1999, and upon its success combined most of the gothic monsters for 2004's Van Helsing, in the hopes of going through Universal's entire stable of beasties. It didn't work out, and neither did Universal's attempt to give another shot to The Wolf Man.
 * Godzilla. Obviously, the Big G is the star of the line, but Mothra is important enough for her own subseries, and pretty much anything by Toho can be worked into a Godzilla film. And, of course, the big lizard himself can be crossed over with just about anything.

Western Animation

 * Most animation companies will eventually have all the characters from their shorts shown to exist in one large community. Hanna-Barbera once pooled them all for "Laugh-A-Lympics". Scooby and Shaggy actually joined the team, but eventually split off again, and the Cartoon Network Studios (into which HB merged) will do its own thing with the Scooby Doo property.
 * The Disney Princess brand, which is primarily focused on the royal heroines of fairy/folktale-derived films from the Disney Animated Canon. While no canon work has presented the heroines together (a rejected concept for the "Pomp and Circumstance" segment in Fantasia/2000 would have done so), various direct-to-video productions, theme park shows, CDs, and so forth have.
 * The Disney Animated Canon as a whole can kind of be considered one giant uber franchise.
 * Kingdom Hearts also has most of the Disney Princesses as the Princesses of Heart. Alice replaced Ariel who was instead a Guest Star Party Member
 * The Princess franchise's rival Disney Villains, actually takes this Up to Eleven!

Sports

 * Professional teams are considered franchises in their own right, but the entire league its a brand name it will try to exploit--using the imagery of its various teams.