Catacomb Command Barge
Catacomb Command Barges are repulsor-driven skimmers that act as the personal transports of Necron Lords. Before the bio-transference Necron Lords would ride these barges into battle to motivate their troops with their presence. After becoming machines however the vast majority of Necron troops lost the ability to feel emotions, and with it the ability to be inspired by their lord riding into battle with them. Despite this the barge is still useful, possessing tools which allow the lord to issue commands to all his troops from on board, or amplify his voice across the battlefield, while granting the speed needed to take the lord wherever the battle needs him to go. A lord in a command barge will usually go to the highest point that they can to survey the battlefield and try to figure out what the enemy is up to. The piloting of the craft is handled by the crewmen hard wired into the barge who recieve and flow the lord's commands near instantaneously. This allows the lord the freedom to fight up close should the barge be attacked or swing over the edge of the barge to decapitate some poor fools.
In game the barge is a Chariot skimmer transport for non-special character Lords(they used to be able to take it but it was faq'd out). It comes with quantum shielding making it frustratingly hard to destroy if you dont pen it first. Its rules used to allow the person driving it to avoid vehicle damage by taking a wound himself. This was faq'd and now treats weapon destroyed as crew stunned. It has the option for telsa or gauss cannons. If the barge flies over an enemy unit in the movement phase the lord can make three "sweep" attacks against a unit he flew over, making melee attacks at them. Due to the changes to chariots in 7th should your lord make his reanimation rolls after dying the chariot comes back with him with one hull point remaining.
Catacomb Command Crunch
Now basically a Warscythe with a gun. One of the best HQ for Necrons (after illuminor Szeras), since it is tough and also a character, so you can hide it behind your troops. While pricey (a whole 50 extra points compared to the Overlord), it got solid buffs in 9th Edition granting it an extra Wound, Toughness and Attack (bringing it up to S5 T6 9W). With the fact it can also zip around 12" per turn, it makes for an extremely tough to crack HQ that can position easily to dispense its buffs and fire off beams of Gaussy death. Also, it has Quantum Shielding and anything with Quantum Shielding is great.