Yeah, Corey Feldman was in a number of popular movies in the 80’s and early 90’s (Gremlins, Goonies, Stand By Me) and teamed up with Corey Haim in movies like License to Drive, then seemingly dropped off the planet.
He had some major, well-documented problems with substance abuse (alongside Corey Haim, who later died of an overdose) and I believe that’s what derailed his career. He’s popped up in a few reality shows with other Z-list celebrities.
Now, there are some actors who disappear from show business for more noble reasons. Take Rick Moranis, who was big in the 80’s and 90’s in films like Ghostbusters, Ghostbusters 2, Spaceballs, Little Shop of Horrors, and Honey I Shrunk the Kids. After his wife passed, he quit acting to stay with his kids full-time.
Then there are some who disappear but make big comebacks. John Travolta did almost nothing for years after Saturday Night Fever and Grease, then made a huge comeback in Pulp Fiction. Sean Astin starred in Goonies, Toy Soldiers, and Rudy but only had bit parts for years before playing Sam in the Lord of the Rings movies. Another Goonies star, Josh Brolin, also had mainly bit parts until No Country for Old Men and Avengers made him a household name.