First and foremost, you have two rather popular/rare enchants, Formula: Enchant Boots - Cat's Swiftness and Formula: Enchant Boots - Boar's Speed & Formula: Enchant Cloak - Steelweave. They're two enchants that sell rather well at the auction house, and they're rarely seen because no one really farms Heroic Magisters Terrace any more. I've been able to sell these enchants at 4-500g per, and they sell rather often. It's a great niche market that any enchanter should be in. On top of this, you also get Void Crystals from the epics that drop from the bosses, which can be shattered for 2 large prismatic shards per which can then be used for either of the enchants mentioned above. ( Note- the enchants are BOP you're selling the scrolls )
Then you also have a ton of epic patterns that drop in here, you have Pattern: Cobrascale Gloves, Pattern: Netherdrake Gloves, Pattern: Gloves of the Living Touch, Pattern: Cobrascale Gloves, Pattern: Windstrike Gloves. The recipes are BOP but the craftables are BOE, you could craft some and if you're on a server that has some level 70 twinking, you'd be able to get a nice profit for some of these items.
There are also a ton of rare BOE recipes & patterns that drop within here. To name a few: Recipe: Haste Potion, Recipe: Elixir of Empowerment, Plans: Adamantite Weapon Chain, Schematic: Mana Potion Injector, Schematic: Healing Potion Injector, Pattern: Unyielding Bracers, there are more but I'll stop there, I'm sure you get the point. Most of these patterns can yield an easy 1,000-2,500g, sometimes even more if you find the right buyer.
If that's not enough for you to go farm this place,
you also have a pet, namely the Phoenix Hatchling. It's an awesome pet that have if you ask me. But wait that's not all! There is also the mount, Swift White Hawkstrider, which I've wanted for years ( 2 to be exact :P ). You also have the Orb of the Sin'dorei, which transforms you into a blood elf, it's just a fun little vanity item.
So what have you learned today? Well.. hopefully after reading this post that you'll have some incentive to go out and run a couple Heroic Magister's Terrace runs, for a chance at making a couple thousand gold, a pet, a mount and a nice little vanity item.