Gnomeregan is a pretty odd instance, due to the fact that there is a safe haven in the middle of the instance, with vendors, repair-stations, quests and a mailbox. Due to it being a Gnomish city (And gnomes who posses a very advanced understanding about futuristic technology) it has a very vast amount of technical devices and others.
Bosses of Gnomeregan
Gnomeregan consists of 7 bosses, with the last boss being Mekgineer Thermaplugg.
Grubbis & Chomper
Grubbis and Chomper are both spawned at the end of the Blasmaster Emi Shortfuse's Event. Grubbis is a trogg and Chomper is his basilisk pet. Though they are spawned at the same time, they are both considered individual bosses. Grubbis can drop rare-quality mail gloves but his pet Chomper drops nothing of worth.
The Viscous Fallout is a tainted water elemental created due to radiated oozes taking over a part of the city. He can drop one of three rare-quality items: a pair of cloth boots, a dagger or the special Hydrocane, which is a staff that allows you to breathe underwater.
The Electrocutioner 6000 is a Spider Tank, controlled by a lieutenant leper gnome. Amongst his other loot, he is the one boss that drops the Workshop Key, which allows entrance into the backdoor of Gnomeregan, making it a lot quicker to get to the last boss for those groups that are uniterested in the first part of the instance. He can drop one of three rare-quality items: A ring, a one-handed sword or some cloth bracers.
Crowd Pummeler 9-60
The Crowd Pummeler 9-60 is a gnomish Mech built to maintain to sentry Gnomeregan. However, today they are tinkered with, and views your group as intruders needing a bashing. The Crowd Pummeler 9-60 can drop one of two rare-quality items: A pair of leather boots or a two-handed mace.
Dark Iron Ambassador
The Dark Iron Ambassador is a rare spawn in Gnomeregan, and can be seen patrolling between Sicco Thermaplugg and the Dark Iron dwarves. He can drop one of three rare-quality items: A pair of leather bracers, a gun or a one-handed mace.
Mekgineer Sicco Thermaplugg was once a promising tinker with a lot of amibition. He dreamt of becoming a true king of Gnomeregan - One which they had not seen for almost four-hundered years. However, they chose his best friend, Mekkatorque, over him, and that was the end of his sanity. Eventually, Gnomeregan was infested with troggs, and after weeks of debating, Thermaplugg convinced Mekkatorque to plant a bomb that would kill the troggs by radiation. The case worsened when he convinced the High Tinkerer, Mekkatorque to open the flood gates, spreading the effect of radiation across the entire city. However, just before the blast, he found himself locked inside Gnomeregan. He did not die, but as most of the Gnomes, he got changed into leper beings, cursed with even more insanity. In the midst of all this, he began calling himself king, and the leper gnomes answer to him, as they fight off any intruder of Gnomeregan.
This is one of the first boss encounters where you actually have to d something else then just hit on the boss. Around Thermaplugg sits about six pillars, which individually begin spitting out bombs. These bombs can be lethal to your group, and has to be dealth with immdiately. Dealing with them doesn't mean killing them, which will just make them explode. Dealing with them means pressing a button, one located on each pillar, which will shut off the bomb spawning.
Once Thermaplugg is dead, you can loot him for one of four rare-quality items : A cloth helmet, a shield, a two-handed axe or a ring. He can also drop two engineering schematics.
Quests of Gnomeregan
Gnomeregan have quests for both Alliance and Horde players.
Save Techbot's Brain!
This quest is a follow-up from a quest called Tinkmaster Overspark
. Tinkmaster Overspark wants you to go kill Techbot and remove his memory-core, and bring it back to him in Ironforge. Techbot is located outside of Gnomeregan. You will be rewarded with 20 silver, about 2650 experience and 350 Gnomeregan Exiles reputation.
You have to go into Gnmomeregan and kill one of the irridiated Trogg there, using the quest item on them to retrieve the 'green glow' from them. This might show up as 'failed' a couple of times before you actually get the quest item. Keep on trying until you get it. If you bring the Green Glow back to Ozzie Togglevolt you will be rewarded with 22 Silver, 250 Gnomeregan Exiles reputation and about 2200 experience.
The Only Cure is More Green Glow
You have been sent out yet again to get more Green Glow, but this time around you have to get radiation from one of the irridiated slimes of Gnomeregan. You have to use the vial on a LIVING irridiated slime, and even now it can fail, making it a bit tougher then before. In addition, you have two hours to bring back the fallout to Ozzie Togglevolt before it 'fades' and you will have to do it all over again. You will be rewarded 25 Silver and around 2200 experience.
This quest from Master Mechanic Castpipe takes you yet again into Gnomeregan to retrieve a Prismatic Punch Card. You have to retrieve a white punch card from mobs outside the instance, and upgrade it at various consoles throughout the instance. Nearing the very end of the instance you should have your Prismatic Punch Card, and thus be finished with the quest. Bring the card back to Master Mechanic Castpipe to recieve 25 Silver and a choice between an uncommon-quality cape or two-handed mace. It also gives you 500 reputation with Gnomeregan Exiles and about 3650 experience.
Klockmort Spannerspan wants you to bring back 12 Essential Artifacts to him. These are found in containers throughout Gnomeregan and getting 12 shouldn't be a problem at all in a full run of Gnomeregan. The rewards for this quest is about 3650 experience, 500 reputation with Gnomeregan Exiles and 55 silver.
Shoni the Silent in Stormwind wants you to go to Gnomeregan and kill mechanicals and bring back 24 of their Robo-Mechanical guts. Doing so will result in a reward consisting of about 2450 experience, 250 reputation with both Gnomeregan Exiles and Stormwind plus a choice between two uncommon items: Either an off-hand axe or some cloth gloves.
The Grand Betrayal
The Grand Betrayal is the 'ending' quest of Gnomeregan, thus also being the one with the highest level requirement and the best rewards. High Tinker Mekkatorque wants you to end his old friends self-promoted reign of Gnomeregan. Simply kill Mekgineer Thermaplugg, the last boss and this quest is completed. The reward is one of three rare-quality rewards: A cloth robe, some leather pants or some mail pants. In addition, you will recieve 35 silver, about 4950 experience and 500 reputation with the Gnomeregan Exiles.
This quest will have you kill Mekgineer Thermaplug, the last boss of Gnomeregan, to get the safe combination, which opens a safe that contains some blueprints who you have to steal for Nogg in Orgrimmar. The rewards for this quest is about 2750 experience, 500 reuptation with Orgrimmar and a choice between one of three rare-quality rewards: A cloth robe, some leather pants or some mail pants. Continue with this quest chain to get the ability to teleport straight from Booty Bay to Gnomeregan.
The Sparklematic 5200!
The Sparklematic 5200 is really just a simple event where you exchange a Grime-Encrusted Object and 3 silver for a box containing something of worth..or something worthless. This is a repeatable quest.
The Grime-Encrusted Ring is dropped by a Dark Iron agent and is finished in the same way as the above quest, The Sparklematic 5200. Just place it with 3 silver in the Sparklematic, and you will complete the quest.
Return of the Ring
When you have removed the grime encrusting from the ring, you will get this quest. You will recieve an uncommon quality ring which you can either give back to its owner or keep. Alliance players will give this back to Talvash del Kissel in Ironforge, whilst Horde gives it back to Nogg in Orgrimmar. These quests will have follows up where you have to find a bunch of materials to imrpvoe the ring to something even better.
A Fine Mess
This quest can be found from a Goblin in one of the holding cells to the right after walking out of the safe haven in Gnomeregan. He wants to get escorted back to Clockwerk Run exit, and if you complete this you will recieve 2450 experience and one of two uncommon quality items: A pair of mail bracers or a pair of cloth shoulders.