The list of default contexts for the sound theme are:

Table 1. Standard Contexts

Alerts Sounds to alert the user of an action or event which may have a major impact on the system or their current use, such as dialog-error. alert
Notifications Sounds to notify the user that the system, or their current use case has changed state in some way, e.g. new email arriving, new non-critical update available... notification
Actions Sounds that give the user feedback on their actions. action
Input Feedback Sounds that give direct response to input events from the user, such as mouse clicks or key presses. action
Game Sound used in games. game