Liverpool have also never been relegated from the Premier League, staying in the top-flight since 1962/63. Next up and somewhat surprisingly, Everton have also never been relegated from the Premier League, and hold the second-best record for longest time without a relegation.
City were co-founders of the Premier League upon its creation in 1992, but after finishing ninth in its first season they endured three years of struggle before being relegated in 1996.