There are many city-planets in Star Wars canon, ranging from the galactic capital of Coruscant to the Hutt homeworld of Nar Shaddaa. Inspired by Isaac Asimov's Foundation novels and short stories, George Lucas always intended the capital of the Star Wars galaxy to be a city-planet (also known as an ecumenopolis). Novelist Timothy Zahn honored this when he introduced the planet Coruscant in his "Thrawn trilogy," and Lucas incorporated this world into the prequels. Since then, though, there have been several other Star Wars city-planets.
Not all of them are canon, of course. Over the decades, the Star Wars Expanded Universe introduced many city-planets; these stories were branded non-canon (or "Legends") when Disney acquired Lucasfilm in 2012, though, so they shouldn't really be counted. Although some have been name-dropped in Star Wars ever-expanding canon since, some worlds seem to have been switched up significantly, so this list will only mention city-planets confirmed in canon.