Here's a list with all commands you can use ingame:

.help - Lists all commands you are allowed to use, including event commands when available
.decompose <item> [max count] - Opens decomposable items like bundles, chests etc. (optionally only up to the max count)
.del <item> - Deletes the item from your inventory
.gmlist - Lists all available team members
.id <quest | item> - Shows quest/item/npc IDs (npcs must be in your target)
.noexp - Enables/disables your ability to gain experience
.preview <item(s)> [color] - Previews equipment, optionally in the specified color
.pvp <join | leave | info> - Join/leave the custom PvP-Map where you can fight against the opposing faction

Explanation:
Parameters enclosed in <...> are required. [...] are optional parameters. If separated by | only one is needed, for example: .pvp join OR .pvp leave.
<item> - An item ID or item link (CTRL+right click on an item in your inventory (I))
<quest> - A quest ID or quest link (CTRL+right click in your journal (J))
<color> - HEX-Color Code, Dye item link or ID, or text (e.g. white)