Some commands you should know about:

dwho <weyr> Riders/dragons currently connected
pair <rider or dragon> Dragon/rider pairing info
dtulist <color or Weyr> List all dragons, or certain colors or Weyrs

Specific to Fort are the following commands:

fort wings Breakdown of all the riders by Wing

fort index Gives you a list of these commands and a few others

fort roster Lists everyone in the Weyr and lists by occupation

Puppet information (from the help file):

@addfl <code>=<obj#> Adds a puppet with the code <code> to your control unit

cd<code> <action> Forces the puppet to do something, e.g. pose or go through exits
fl-list List of controlled puppets with codes
fl-find List of puppets with their locations
@remfl <code> Deletes a code from your control unit
@set <obj#>=puppet This lets you see what your object sees. Reset by @set #<obj>=!puppet
@set <obj#>=O The OOC flag, this allows dragons to talk

Dragon Telepathic Links (DTL):

You can add channels to speak with other dragons. You can quiet the pros you receive or even block out another dragon if you are getting spammed. Be courteous in using the "pro all" command. Not everyone needs to hear your dragon mind-tickling your friend's dragon at Fort.

pro all=<message> Primary DTL projection sent to all dragons, sends <message>
pro weyr=<message> To all dragons of your Weyr. Note: not 'pro Fort=<message>. Just 'weyr'
pro <rider or dragon>=<message> A specific dragon
pro <channel>=<message> A specific channel

channels Shows the DTL channels you're on
addchannel <channel name> Adds a DTL channel
delchannel <channel name> Removes a DTL channel
cwho <channel name> Who's listening to the channel

quiet channels Blocks out all but personal messages
quiet all Blocks out all messages
quiet on Blocks out all but channels and personal messages
quiet off Removes blocks

Personalized dragon messages (use @messages #dragon). Some of the most common are:

@omount # is "%N clambers up %T's neck and settles in between two neckridges."
@odismount # is "%N slides from %T's neck and lands gently on the ground."
@mount # is "You clamber up %T's neck and set yourself between two neckridges."
@dismount # is "You slide gently down %T's neck and land with a soft thud."
@go_btw # is "winks into ::between::!"
@from_btw # is "blinks in from ::between::!"
@looked_at # is "I sense %N looking at me."
@mounted # is "Astride %T is "
@lizard # is "Perched on a neckridge is, "
@things # is "%T is also carrying: "
@riderdismount # is "%T rumbles wistfully in your mind as you dismount."
@oriderdismount # is "%N swings down from %p lifemate %T's neck."
@ridermount # is "You feel soft mental reassurance as you mount your dragon."
@oridermount # is "%N swings up to %T's neck, settling between two neckridges, and smiles down to %p lifemate."

@mood # is ""

@astride #6262 is "Astride %N"