Top 5 that I've actually seen play (since 1995). I take 'legend' to imply some sort of judgement about their emotional significance, their longevity in the memory, their affiliation with the club, and so on, rather than simply their footballing ability. Given the time period I've been watching City, a list that simply consisted of '5 best players' would all be from the current squad.
Goater
Andy Morrisson
Kompany
Horlock
Uwe
Some attempt to do an 'all-time' legends list, simply based on what I've heard and read. I never saw any of these play:
Meredith
Bell
Young
Trautmann
Roy Paul