Football fans have the Super Bowl. Soccer enthusiasts have the World Cup. Cinephiles have the Academy Awards.

For pop-culture lovers—the self-professed geeks and nerds who delight in fantasy-inspired fun from anime to zombies— there is Comic-Con, the Olympic-sized celebration of movies, TV, video games, costumes and pop art that began as a humble comic-book convention 43 years ago and is now an annual marketing extravaganza.

Since Thursday, more than 100,000 pop-culture aficionados flooded the San Diego Convention Center, showing off their Storm Trooper suits, playing yet-to-be-released video games and attending panels featuring A-list filmmakers like Peter Jackson and such hot TV shows as Game of Thrones.

But first came Wednesday's "preview night." Available only to those who bought four-day passes to the sold-out convention, the showing is decidedly low tech, yet high end: it's all about collectible toys.

On display were special-issue, limited-edition playthings and books made just for the pop-culture fest. These include not only the unique freebies that various booths were giving away, but also coveted collectibles that could fetch hundreds of dollars at Comic-Con and hundreds more in after-market sales.

Collectors literally ran across the massive convention center floor when the doors opened Wednesday evening to cue up for products like Hasbro's S.H.I.E.L.D. Super Helicarrier, a four-foot-long replica of the flying superhero headquarters from the Avengers movie and Mattel's quirky Dana as Zuul Ghostbusters figurine. Others seek out small-run exclusives such as the golden Domo bobble-head doll (only 1,000 made) and Image Comics' special hardcover comics collection "The Walking Dead: Compendium One" (only 900 available).

Toy companies and publishers large and small make special products just for the Comic-Con crowd. Hasbro and Mattel each issue around 10 Comic-Con exclusives a year. These toys are introduced at Comic-Con and limited numbers are often made available for sale later at Toys "R" Us and on each company's collector websites.

For most collectors, though, adding exclusive items to a carefully cultivated collection is priceless.