The Land Raider is a versatile design, though few have sought to make changes to the basic armament and hull. However, there have been some notable variants designed.
Land Raider Lightning
The Land Raider Lightning is a variant created in 734.M35 by the White Scars in order to have a heavy vehicle more suited to their style of fighting. It was created by replacing the twin-linked lascannons in the sponsons of a normal Land Raider with twin-linked autocannons. The autocannons still provide decent anti-tank fire, and have a significantly higher rate of fire than lascannons. However, unlike the modified weaponry of the Crusader, the Lightning's alternate weaponry does not free up any transport space, as the ammo boxes for the autocannons take up the same space that was formerly occupied by the lascannons' energy containment boxes.
Land Raider Gamma
The Land Raider Gamma was created by the Raptor Legion as an attempt to modify the basic Land Raider into a "fast attack" version. The only modification made was to increase the power of the Land Raider's engines, in effect increasing its speed. Modifications were put in place to increase its traction and maneuvering, keeping the Gamma from being bogged down in difficult terrain or having too much trouble going into a turn.
Land Raider Arista
The Arista variant of the Land Raider was created by the Tech-Priests of Arista in an attempt to have a "bike transport". The Land Raider's inner hull was heavily modified and rearranged, creating a compartment capable of holding a squadron of 5 Space Marine bikes and "launching" them into battle when it was close up to the opposing army. This created a tactical surprise for some Space Marine Commanders to use in battle, running the heavily armed and armour Arista into the heart of the enemy battle lines and unleashing its cargo of bikes. The only drawback to this variant is that the modifications made to the inner hull made it impractical to carry anything other than bikes, and so few chapters use the Land Raider Arista.
Land Raider Ballista
In the Siege of Gharok in 989.M39, the Techmarines of the 1st Company of the Iron Hands were presented with a challenge: create a siege vehicle able to withstand heavy firepower, deliver punishing firepower, and possibly carry troops into battle. The initial planned vehicles were all impractical with the available materials. But one Techmarine, by the name of Fastius, had an idea that was accepted. Many of the chapter's Land Raiders were on Gharok, transporting Iron Hands squads into battle. Four Land Raiders had taken heavy damage, and were set aside for repairs. Fastius' idea was to modify a Land Raider hull to carry a Demolisher cannon into battle.
The first problem with this idea was where to place the Demolisher cannon. Fastius came up with a set of modifications to the upper hull of a Land Raider that would allow it to be placed in a turret atop the Land Raider's hull. Then came the problem of where to place the ammo. Fastius had the sponsons of the damaged Land Raiders removed and placed what could be salvaged of them in storage as spare parts for other Land Raiders. This left a lot of space inside the Land Raider where the sponson weapons' ammo had once been stored. This space was converted into an ammo storage area for the Demolisher cannon. With the Demolisher's ammo stored where the lascannons' energy banks had been, the inner hull still had space to carry ten Space Marines into battle.
The end result of all of these modifications was the Land Raider Ballista: A heavily armoured siege tank able to transport ten power armoured or five Terminator armoured Space Marines into battle.
Land Raider Hammer
The Land Raider Hammer was created as the end result of a botched assault by the Marines of the Silver Hands chapter of Space Marines on the rebel stronghold of Ospris IX. The initial battle went horribly against the Silver Hands, and they lost several vehicles in the attempt. Two of the vehicles resigned to the scrap heap were a Land Raider and a Whirlwind. The Land Raider's upper hull had been riddled with heavy fire, destroying most of the equipment located there, including the upper weapons (twin-linked heavy bolters, hunter-killer missile launcher, and pintle-mounted storm bolter). The Whirlwind's main hull was shattered, but the missile launcher was still intact.
The Techmarines who were participating in the Ospris campaign came up with an awkward fix for this problem: replace the Land Raider's upper hull with the Whirlwind's weaponry and some spare equipment from other damaged Land Raiders. The result was the Land Raider Hammer, a Land Raider armed with two sets of twin-linked lascannons and a Whirlwind missile launcher. The trade-off of all of this firepower was a heavy reduction in the vehicle's speed. The Hammer proved a successful vehicle in its first confrontation, peppering the rebel forces with missiles from the Whirlwind launcher and destroying tanks with its lascannons.
The original Hammer had a flaw, which forced it into "early retirement." The Machine Spirit had been destroyed in the initial conflict, and this plagued the Hammer with problems ever since. The Techmarines of the chapter insisted on giving the "dead" machine a proper retirement and placed it in a shrine in the SIlver Hands' fortress-monastery. All Land Raider Hammers created after the first have had a Machine Spirit.
Land Raider Infernus
Shortly after the creation of the Draconians chapter, ts Techmarines decided the chapter needed a heavy armoured personnel carrier that was more suited to their method of warfare. Their preferred weapons included all melta and flame weapons. To this end, the Techmarines decided to modify one of their Land Raiders. The twin linked heavy bolters mounted atop the Land Raider's hull were replaced with a multi-melta, and the sponson lascannons were replaced with inferno cannons. This gave the newly created Land Raider Infernus considerable firepower. However, after just three battles it was obvious that the vehicle would need some modifications to make it more suitable for its role in delivering troops. The solution came from the Crusader, and its frag launchers mounted to the sides of the front troop hatch. This allowed the Infernus to get in close, unleash a devastating amount of firepower from its weapons, and then let out the troops it was carrying with the cover of a hail of shrapnel. The Infernus has been a great success, and has become the Draconians' preferred armoured fighting vehicle.
Land Raider Null
During the Third War for Armageddon, a contingent of Marines Errant were surrounded and cut off from Imperial forces at the foot of Hive Tempestora. Miraculously a few squads were able to break out through a hole in the Ork lines, but not before suffering severe casualties and losing most of their vehicles. In the end, the only vehicle left was a badly damaged Land Raider, devoid of all weapons. Even without wapos,thi hicle served its purpose, allowing sixteen Marines Errant to ride to freedom through the Ork lines, all that was left of the two companies caught by the Orks. Once these sixteen Marines were back with Imperial forces, they refused to scrap the Land Raider that had taken them to safety. Without any replacement parts and having no compatible weaponry nearby, the vehicle was patched up and left weaponless. Without any capacitors for lascannons or ammunition cases for heavy bolters, the Land Raider was now able to carry sixteen Marines, packed somewhat tightly. It came to be known by the Marines Errant as the Land Raider Null, so named because it had no weapons remaining. The Marines Malevolent, however, viewed it in a very derogatory manner, and nicknamed the vehicle "Rolling Suicide".