HARTFORD, CONN. — The stars were out at 9:30 a.m. in the Connecticut Convention Center.

The top floor of the sprawling complex looked like the pages of a ’90s issue of “Teen Beat” had come to life. Joey Fatone and Chris Kirkpatrick from ’N SYNC talked to a line of reporters. Melissa Joan Hart, the star of “Sabrina the Teenage Witch,” joked about all the men she had made out with (in a professional capacity) over her career.

Of course, it wasn’t exactly like “Teen Beat.” Mr. Fatone, 46, was talking about his children; Mr. Kirkpatrick, 51, was recovering from shoulder surgery; and Ms. Hart, 46, was filming TikToks. (Also, “Teen Beat” stopped publishing years ago.) The stars of the ’90s had grown up. But over one weekend in mid-March, Hartford, often called the insurance capital of the world, transformed into a buzzing, celebrity-filled, sold-out portal to an age of neon windbreakers, sugary breakfast cereals and slap bracelets. It was the second annual 90s Con.

“People are feeling nostalgic about better times,” said Liliana Kligman, 38, one of the founders of That’s 4 Entertainment, the company behind 90s Con. To her, the appeal of the decade is clear: “Social media wasn’t around, it was just the beginning of the internet and the beginning of that technology that, nowadays, takes away from us being connected.”

Downstairs, some of the 13,000 attendees who traveled from across the country began streaming into the venue. The visitors ranged from older millennials, with their own children in tow, to Gen-Zers. They wore flannel, Dr. Martens, butterfly clips and many versions of Alicia Silverstone’s yellow plaid skirt suit from “Clueless.” (Ms. Silverstone was one of the stars in attendance.) In addition to travel and accommodations, weekend passes for the event cost $125 for general admission and $250 for VIP passes.

About half of the exhibit space had been covered in photo booths, outfitted with ring lights, hand sanitizer and cash boxes. Behind each, celebrities like Tori Spelling, Jason Priestley, Candace Cameron Bure, Danica McKellar and Dave Coulier would later sit patiently, waiting to greet the crowds.

Admission tickets did not include the price of celebrity photos, all cash only. Snaps with the 49 celebrities in attendance cost anywhere from $50 (Danny Tamberelli from “The Adventures of Pete & Pete”) to $280 (for a group shot with the cast of “Charmed.”) Unauthorized photos were prohibited.

The event was not about the ’90s in a broad sense. It was not a comprehensive ode to the last decade of the 20th century, an era spiritually book-ended by the fall of the Soviet Union on one end and Sept. 11 on the other. It was not even a celebration of the adult-focused entertainment of the era. References to “Seinfeld” and “Friends,” for example, were conspicuously absent. It was a three-day bonanza of photo ops and panels dedicated to the (largely white) TV shows, movies and music that young millennials inhaled like Fruit Roll-Ups while those other, thornier aspects of the decade roiled around them.

The origin story of the convention is simple enough. Ms. Kligman and her co-founder, Christina Figliolia, 37, are also responsible for organizing Christmas Con in New Jersey and Kansas. They are both children of the ’90s and realized, despite the ubiquity of fan conventions, a 90s Con didn’t exist yet. So they put it together as a chance for fans to meet the casts of their favorite childhood entertainment, and, as Ms. Figliolia put it, “step back in time with them.” They chose Hartford because it was a city within driving distance of their core base for Christmas Con. They are planning another 90s Con in Tampa, Fla., in September.

Ms. Hart was one of the first celebrities that signed on for 90s Con. Ms. Kligman and Ms. Figliolia said they worked with Ms. Hart since their first Christmas Con in 2019, and through her, brought on the rest of the “Sabrina the Teenage Witch” stars, like Caroline Rhea and Beth Broderick. “They were the first core show that we got,” Ms. Kligman said.

It was savvy timing, too. Over the past few years, ’90s style has returned to the mainstream. TikTok is brimming with “90s outfit inspo” videos, where creators share pictures of themselves in high-waisted, straight-leg jeans and oversized blazers. On Instagram, one account that shares photos and videos from the decade has 2.4 million followers. And every few months, photos of Princess Diana in sweatshirts and bike shorts will send the fashionable and the online into paroxysms of delight.

This could be a cultural harkening back to what Ms. Kligman described as a “better,” more connected time. Or it could simply be that the ’90s were due for a comeback.

Entering the venue, attendees were greeted by the sight of “Saved by the Bell” star Mario Lopez gazing at the long line of people in front of him like a benevolent TV king surveying his followers.

One by one, visitors approached, first handing over fistfuls of cash to one of Mr. Lopez’s handlers, and then coming around the table for their picture. Mr. Lopez greeted everyone warmly, wrapping his arm around each fan. Beyond him, his former co-stars Elizabeth Berkley and Mark-Paul Gosselaar did the same.

In front of Mr. Lopez’s booth, Jessica Bromberg-Alvarado, 36, a volunteer, was enforcing the rules. “No pictures!” she shouted, waving her arms in front of smartphones when visitors tried to snap free, unauthorized shots of the star.

Ms. Bromberg-Alvarado had attended last year’s convention as a visitor and loved it so much that she decided to be a volunteer this year.

“It was a life-changing experience for me, because I’m a Backstreet Boys fan, and I got hugs from A.J. and Nick,” she said. “When I went up to A.J. I had no words because it was enough just to be in his presence.”

Ms. Hart (whose individual photo ops started at $70) admitted conventions made her uneasy at first.

“The first one I ever went to, I felt very uncomfortable about taking money for autographs and photos,” she said. “If you run into me on the street, I’m not going to charge you for a photo. So it felt weird to me.”

She said she overcame her discomfort by talking to friends who loved the convention experience. “It does give an outlet to people who want to be here,” she said, adding: “My 10-year-old is dying to come to one of these in case he meets Millie Bobby Brown.”

And fans are willing to pay a lot for the experience. While standing in a line to get photos laminated, Jared McFadden, 27, said he had spent “like a thousand dollars” just on his plane ticket to the convention. Rachel Stegel, 29, and Alyssa Williams, 35, traveled from Maine. Both were holding stacks of photos and said they hadn’t yet tallied up the cost. “We don’t want to know,” Ms. Stegel laughed.

Visitors could also attend panels where the casts of shows like “Full House,” “Beverly Hills, 90210” and “Charmed” talked about working together, whether they have group texts and possible reboots.

Guests could also peruse the booths that sold toys and VHS tapes, get a Furby tattoo or put on a disposable coverall and have neon green slime splashed over their heads like the Nickelodeon stars of yore.

At a costume competition, attendees dressed as Beanie Babies and characters from “Hocus Pocus.” The top award ultimately went to two small children in wigs dressed as Wayne and Garth from “Wayne’s World.”

Kendra Daniels, 33, from Las Vegas, spent hours on her costume — Cynthia, Angelica Pickles’s doll on “Rugrats.” She said nostalgia brought her to the convention.

“These are the best celebrities, the best shows we could ever ask for,” Ms. Daniels said. “It’s just a comfort. It’s what we grew up watching, and it’s magical.”

Nostalgia can yield psychological and social benefits and help us maintain our sense of identity when the world feels chaotic, according to Dr. Krystine Batcho, a psychology professor at Le Moyne College in Syracuse, N.Y., who studies nostalgia.

In an email, Dr. Batcho said that nostalgia provided “a bit of escape to a ‘simpler, safer’ time when we had fewer worries, obligations and fears of potential failure, abandonment or disappointment.”

Dr. Batcho also noted that research had shown the effectiveness of nostalgia as a marketing strategy. “Along with the desire for ‘possessing a piece of the past,’ nostalgia is a comforting emotional state that can (at least temporarily) mask the normal anxiety that would inhibit impulsive or excessive spending,” she wrote.

Later that evening, there was an after-party in the convention center’s main ballroom. There was a parquet dance floor and a large D.J. booth where Rockstar DJ Tre performed. He played the Macarena, ’N SYNC and “Jump” by Kris Kross.

Long lines snaked from the three bars on the sides of the room. In the corner, best friends, Shawn O’Connor, 35, and Joe Odermatt, 34, sipped beers. Mr. O’Connor runs Nostalgia, a ’90s-themed bar on Long Island. He said revisiting the decade made him feel like a child again.

“It makes me happy,” he said, “and I want to feel happy because I’m old.”