Can you still play delisted games?

Can you still play delisted games, even though they're no longer available for purchase or download from official stores? I've heard rumors that some gamers have found ways to access these titles, but I'm not sure if it's SAFE or legal. Is there a way to play these games without breaking any rules or risking malware? And if so, how do you go about doing it? I'm curious to know if there's a way to enjoy these older games without resorting to illegal or unsafe methods.