Throughout the history of the universe, there have been multiple timelines, alternate realities and parallel universes that have contained versions of the Galaxy-class starship USS Enterprise-D, as well as various duplicates.
By the late 24th century, Starfleet held replicas of ships named Enterprise at the Starfleet Museum of Deep Space Exploration. (SOTL - Ships of the Line 2014 calendar: March image, "Acquisition")
In 2370, the Enterprise was equipped with an experimental saucer section while its own primary hull underwent repairs. (TNG novel: Rogue Saucer)
In 2411, replicas of the Galaxy-class Enterprise-D were in service and underwent technological upgrades and refits. (STO website: The Legendary Command Exploration Cruiser)
In an anti-time future experienced by Captain Jean-Luc Picard in the year 2370, the Enterprise had been refitted with a third warp nacelle, a cloaking device, could reach warp 13, and included additional weapons and systems. Vice Admiral William T. Riker prevented the ship's decommissioning and used it as his personal flagship circa 2395. It was destroyed in the anti-time anomaly in the Devron star system, alongside anti-time past and anti-time present versions of the Enterprise-D. (TNG episode & novelization: All Good Things...)
In a different quantum reality, Captain Riker had to abandon the saucer section after the Borg won the Battle of Wolf 359 and assimilated Earth. The prime Enterprise joined forces with Riker's remaining engineering hull to defeat the forces of Locutus. (TNG comic: "The Worst of Both Worlds")
In the Odysseyan Pass, the USS Enterprise-E encountered an alternate Enterprise-D in the year 2386. The crews worked together to bring everyone, including a Romulan Vas Hatham-class bird of prey, home. Before their return, Captain Picard gave the alternate Captain Riker the schematics for transphasic torpedoes. (TNG novel: Headlong Flight)