We can be sure that Chayenne is responsible for the following content:
Realm of Dreams (We use her key in the Quest)
The Lightbearer Event
Vengoth / Blood Brothers Quest
Eclesius
Unnatural Selection
Travora and Marriage System
Svargrond Arena
„Chayenne: "The Lightbearer Event was designed to really make communities work together on a big scale. At first, when I started creating the event design, it was 'my little project'”
Source: https://www.tibia.com/news/?subtopic=newsarchive&id=1135
„For me it depends how much time I have besides organising everything. I like to design large and story-filled questlines as well such as Blood Brothers, but also small and fun bits like Eclesius' quest or Unnatural Selection. I also implement most new features such as the content side of the marriage system or Travora and love to chew complicated scripts and riddles over.”
Source: https://www.tibia.com/news/?subtopic=newsarchive&id=1189
“From this desk, the world of Tibia is formed. This is the work place of Chayenne, the lead game content designer of CipSoft. Besides organising the content production for Tibia and TibiaME, she brings many of her ideas to life in Tibia. For example, the Castle Vengoth, the Blood Brothers quest and the Svargrond Arena”
Source: https://www.tibia.com/news/?subtopic=newsarchive&id=1719
We may suspect some of the other locations/content to be the work of Chayenne but there is no 100% proof. The list remains open. Maybe someone will find other locations with evidence.