Igor's Mass Auction (IMA) allows you to create up to 18 auctions at once. A new tab appears in the Auction House. I am not the original author - I merely updated it to work like it used to, that is, with auctioneer.

Two new dropdowns appear in the pricing method menu. The 'Auctioneer' option is the simplest one which uses the market price as calculated by auctioneer. The Auc-undercut will always attempt to undercut the competition. Do a fresh scan, and set your %undercut settings in Auctioneer settings.

A new button allows you to put all your items in the Auction House at once. No more clicking 18 times in a row. A new button will scan the Auction House for all items in your bags. Great for getting the most up-to-date prices.