From Citizens Wiki

Characters are addons that use the Citizens API to add functionality to existing NPCs. To get addons on your server, simply follow the links to their respective wiki pages and find the download link. Install the characters' JAR file into the /plugins or /plugins/Citizens/plugins directory.

Citizens NPCs can contain multiple traits at the same time. See Multiple Traits

Suggested Addons

There is no guarantee of any of these still being available/updated. If you would like to be added to the list please message the team on Discord.

There are also many addons available outside of the wiki.

Name Developer Description
Builder jrbudda/mcmonkey Build schematics, block by block.
Denizen mcmonkey Scripting engine that supports advanced and easy control of NPCs.
DtlTraders dandielo Another trader character.
Quests Various Links to Quest options for Citizens 2.
Sentinel mcmonkey Sentinel combat NPCs.