Citizens is an NPC plugin in the vein of the old hey0 ones, aimed at creating NPCs that perform a variety of tasks. It adds various NPC types, from simple NPCs that talk to lively, active Guards. Originally featuring only one type of NPC, Citizens now contains 7 toggleable types and 1 creature type. With the Citizens API, plugins developers can make their plugins compatible with NPCs. Server admins are even able to choose which types that they want on their server.
https://dev.bukkit.org/projects/citizens/
Command Reference
http://wiki.citizensnpcs.net/Main_Page
Permissions
citizens.admin Ability to use all Citizens commands and edit all NPCs (basically an Op for Citizens).
citizens.npc.talk Ability to right-click an NPC to make it talk or to hear it talk when close
citizens.help /citizens help
citizens.npc.help /npc help
citizens.npc.create /npc create
citizens.npc.list /npc list
citizens.npc.despawn /npc despawn
citizens.npc.remove(.all) /npc remove
citizens.npc.rename /npc rename
citizens.npc.select /npc select
citizens.npc.character. /npc character
citizens.npc.owner /npc owner
citizens.npc.spawn /npc spawn
citizens.npc.tp /npc tp
citizens.npc.tphere /npc tphere
citizens.npc.lookclose /npc lookclose
citizens.npc.power /npc power
citizens.npc.age /npc age
citizens.npc.edit.equip /npc equip
citizens.npc.edit.path /npc path
citizens.npc.edit.text /npc text
.interact Allows players to interact with an NPC type