Zynga, PopCap, RockYou, CrowdStar, Playdom — this week's AppData list of fastest-growing Facebook games by monthly active users reads like a who's who of the top developers from earlier in the year. The only one missing is Playfish, which has been quiet for several months.

CityVille is continuing its rampage, still adding users at the rate of roughly three million MAU per day, which we noted last week. At this point it looks pretty certain that CityVille will top the 84 million MAU that FarmVille had at its peak.

The growth is dragging other Zynga games up, like FarmVille and Treasure Isle; we've also noticed Zynga advertising a bit more actively over the holiday. And FarmVille 中文版, the Chinese-language version of FarmVille we first spotted Friday, is doing well on its own at number seven.

Monster Galaxy is the number two game, by Gaia Online. At the moment, this is one of the better-looking new games on Facebook, featuring bright, friendly graphics for the tween set. Like the number three game, PopCap's Zuma Blitz, its monetization mostly focuses on powerups, with an open gameplay model that mostly allows users to play for as long as they'd like.

RockYou has Zoo World and Birthday Cards posting small gains, relative to their peak size, while CrowdStar is a bit further down with It Girl and Mighty Pirates. And Playdom's appearance is with City of Wonder, which is actually showing good retention of the playerbase it initially acquired at launch.