To create a subject for a wiki space, you have the following options:

• To create a list of the labels used most frequently in a wiki space, use the Popular Labels macro. For instructions, refer to the Atlassian help page: 

  https://confluence.atlassian.com/conf613/popular-labels-macro-964960897.html

• To create an alphabetical list of the labels in a wiki space, use the Labels List macro. For instructions, refer to the Atlassian help page:

  https://confluence.atlassian.com/conf613/labels-list-macro-964960851.html