Some extremely useful addons for mass auctioning are Auctioneer, Auc-Util-BigPicture, Bulkmail2 and Bulkmail2Inbox.
Auctioneer
You can get the latest Auctioneer package here. It is a great tool and has a lot of functions. To keep it as light as possible I am not using all modules. Here is a list of modules I am using:
!Swatter, Auc-Advanced, Auc-Filter-Basic, Auc-ScanData, Auc-Stat-Classic, Auc-Stat-iLevel, Auc-Stat-Simple, Auc-Util-FixAH, Informant, SlideBar, Stubby
Auc-Util-BigPicture
AUBP is a great plug-in for Auctioneer. It calculates your total worth by adding cash, inventory, banks contents and auctions and gives out a total amount. For example if your total worth is 100k gold and you just spend 2k gold on infinite dust and you put up those infinite dusts for 5k on AH then AUBP will tell you that your Total is now 100k-2k+5k=103k
You can get this tool here.
BulkMail2Inbox
If you are going to post thousands of auctions you might like to consider a tool that gets mail out of mailbox convenient. There is currently a limit of 50 items per minute, no addon can get around that. You get a nice big „Take all“-button to your inbox.
You can get BulkMail2Inbox here.
BulkMail2
If you are going to split up auctions to multiple chars then BulkMail2 is a great tool to automate this. You can define targets for all kind of materials. For example I have Slanty for glyphs and inks, Vertano for cloth, Finewares for high level Essences and Shards, Daisan for lower level Essences and Shards, Exorials for BoE Items and Recipes, Katya for Herbs and Minerals (including primal, eternals, jewels), Slant for all kind of Reputation items. Wherever I have been farming, if I return to town I press 1 button and all stuff is being automatically sent to the correct mule.
You can get BulkMail2 here.
Macros
Take all mail, place a 60 second countdown bar (DBM, deadly boss mods)
/run CheckInbox();
/click BMI_TakeAllButton
/dbm timer 00:59 Mail
Since I am usually alt-tabbing while waiting for the next batch of mails I have another macro that plays an mp3 with 57 seconds of silence and then a voice reminding me „You have mail“.
/run CheckInbox();
/script PlaySoundFile("InterfaceAddOnsAudiomail.mp3");
/click BMI_TakeAllButton
/dbm timer 00:59 Mail
As you can see, it plays the file „Interface/Audio/mail.mp3“. You can find the Audio files I am using here. Just unzip it in your interface folder and the macro will play the sound. I use the second sound file for Maelstrom Weapon!
Alternatively use your own files and directories. Or this macro here which is using the ingame Stopwatch to produce a „ding“ sound after 60 seconds.
/run CheckInbox();
/click BMI_TakeAllButton
/dbm timer 00:59 Mail
/sw 60
/run Stopwatch_Play()
/sw hide