The last song in the South Park episode "Mr. Hankey'sChristmas Classics" is "Have Yourself A Merry Little Christmas," and unlike the others it's unaltered for Rule of Funny. Around the line "happy golden days of yore," there's suddenly a mini-Montage of some of the South Park females, followed by them and others crowding around Author Avatars Stan and Kyle during "faithful friends who are dear to us." All of those characters were originally voiced by Mary Kay Bergman, and this was the first new episode made after her suicide.
The episode after that, "The Red Badge of Gayness," also commemorated Bergman by not having any of her characters speak (Kenny's mom did appear, but was only there to silently read a letter about her son's death while Cartman narrated). The only woman character who spoke was the S'mores Schnapps woman played by Trey Parker, using his Mr. Hankey voice.
Real Life example: She gave Tara Strong, her close friend, a dog for her 26th birthday (the last one Bergman was around for).