The Rhino Transport has seen more permutations than any other vehicle in the 41st millennium barring the Imperial Guard Chimera, and with good reason - it's that damned versatile, and Games Workshop and the Imperium of man both get to reuse the hull from the Rhino (from a logistics standpoint, that's actually a hefty plus. Similar parts means less specialized training and less waste for both the in universe Forge Worlds and Game Workshop). One of several uses for the Rhino involved ripping its troop transport capabilities out entirely, replacing them with ammunition stores, chassis reinforcements, extra armor, and weaponry hardpoints to turn the Rhino into a more conventional tank. The result is the Predator, which has since become the primary battle tank of the Adeptus Astartes. As it was in use extensively during the Great Crusade, you can expect to see it in frequent use with the Traitor Legions as well.
The Predator Tank, being functionally a converted Personnel Carrier, isn't quite the equal of the Imperial Guard Leman Russ in terms of firepower or armor, but makes up for this with superior accuracy, greater flexibility, faster land speed, and being cheaper to field than its Imperial Guard counterpart - traits which carry over to the Tabletop game. A Predator can easily be tailored for either an anti-infantry or anti-vehicle role with equal ease, and costs notably less than Leman Russ to outfit - a Predator Destructor can be outfitted for 100 points, whereas an annihilator costs 165 - both being considerably cheaper than a conventional Leman Russ or one of its tank-hunting variants, with better accuracy as part of a bargain.
All in all, the Predator is a decent and surprisingly overlooked vehicle; players tend to eschew it in favor of other heavy support choices available. - the Predator takes up a valuable heavy support choice, after all. Whilst it lacks the ammo-spewing fury of other Imperial tanks, its firepower is nothing to sneer at and its armor is quite good as well - it's hard to find a more efficient vehicle for a heavy support choice for the points-cost involved. An old saying amongst Marine players of both flavors is that if you have the points and a free slot with nothing else to put in it, you can't be let down by the Predator.
Predators are often organized into common variants, for anti-infantry, anti-vehicle, or close assault purposes. These three common variants, dubbed "patterns," by the Adeptus Mechanicus, are listed below:
Destructor Pattern Predator
AKA, the Predator Destructor. The Destructor is armed with a turret-mounted Autocannon (firing some kind of AP/HE shells as of 8th) and sponson-mounted Heavy Bolters. The most common form of Predator due to its ease of maintenance (and low points-cost), the Destructor offers large amounts of Dakka for a Marine force group, as well as the ability to engage light vehicles with its Autocannon. It lacks, however, the ability to do much damage to enemy heavy vehicles unless it targets vulnerable rear armor with its main gun. Optimized for hunting infantry, the Predator Destructor is a solid choice for an army, though it competes heavily with other heavy support choices for the role.
An efficient and popular modification for the Destructor is to replace the Heavy Bolters with Lascannons, giving the Destructor the ability to reliably engage and destroy vehicular threats, since its main gun is no slouch in the anti-armor department. This particular variant is especially popular amongst Chaos Space Marines, who often fit the vehicle with a Havoc Launcher to make up for the loss of anti-infantry punch, resulting in a much more ubiquitous vehicle overall for 150 points. Rock.
Annihilator Pattern Predator
AKA, the Predator Annihilator. Whereas the Destructor pattern Predator is designed for engaging Infantry, the Annihilator is specially-built to destroy vehicular threats. It is equipped with a twin-linked Lascannon in its turret, and a Lascannon each of its sponsons. This optimizes it for a role as a tank-hunter, giving it extensive anti-vehicle punch at a much more reasonable cost than several tanks specialized to this role, such as the Leman Russ Vanquisher. A full volley of Lascannon fire is sure to give a solid punch against enemy armor, as well as the errant high-value independent character. Fully kitted-out, it's a much more viable anti-vehicle platform than the Terminus Ultra, as it is both cheaper, smaller, and doesn't have a chance of blowing the fuck up, though the Ultra's heavier armor, additional shots and ability to fire at two different targets do make it an attractive option against vehicle-happy armies.
A common modification for the Predator Annihilator is to replace its Lascannon sponsons with Heavy Bolters. This gives it notably higher anti-infantry punch and has the added benefit of giving the Annihilator the ability to launch some serious hate at enemy units trying to close in, making it extremely popular among the Loyalist Astartes (as well as popular amongst tourneyfags, because it's generally is considered the most-efficient use of points for the thing). Sadly, tanks don't have the option of a weapon that makes up for the loss of anti-vehicle weaponry (since the Hunter-Killer Missile is single-shot, as are combi-weapons), which tends to make it a bit less common.
Baal Pattern Predator
The Baal Predator is unique to the Blood Angels, which is designed specifically for urban combat. As such, many of the weapons it has are designed for clearing out troops in defilade or buildings. The primary armament of the Baal is either a twin-linked Assault Cannon, or a Flamestorm Cannon, which is functionally a bulked-up heavy flamer designed to deal with armored infantry, ideally ones inside bunkers or hiding in forests. Its sponsons, likewise, are designed for urban combat - either Heavy Bolters or Heavy Flamers. The Baal thus excels not only in dealing with troops in cover, but in dealing with large clusters of enemy units, such as Orks or Tyranid swarms. Funnily enough, given the weapon loadouts of terminators, you would think this Predator variant would be able to have a flamestorm cannon as its main weapon and use sponson-mounted assault cannons. Oh well, guess that would be too good.
Sadly, the Baal Pattern is only available to the Blood Angels and their descendant chapters. The Blood Angels were the ones who found the STC (Standard Template Construct) for the design during the Great Crusade, and decided that they liked the design a lot. So in a borderline-heretical move in the eyes of some, the Blood Angels refused to show the specs to the Adeptus Mechanicus, functionally deciding to take their Baal and go home... BLAM! Making terrible puns is HERESY!. Apparently it escaped the notice of the Blood Angels that such an act would violate the Treaty of Olympus and would give the Mechanicus every right to pack up and leave the Imperium. Nice going. Good thing the Mechanicus kept their heads and decided to win technologically, instead. Though it does make one wonder why the Mechanicus doesn't just create the pattern themselves since it's made entirely from weapons that they already have the STC for (and this was before the Horus Heresy, so this was the age where the AdMech was still inventing new things without the techpriests lobotomizing the offending heretek with a siege drill). Even without the superior engine it would still be excellent for urban combat. In fact they did; see below.
Deimos Pattern Predator (Forge World)
The Deimos pattern Predator is type of predator tank used during the Great Crusade, based on the early Predator models produced by Games Workshop back in the day and as such, is one of the oldest variants of the standard Predator Destructor main battle tank used by the Adeptus Astartes of the 41st Millennium. Sporting a much boxier hull and a rounded turret like the Fellblade. It is distinguishable from its modern counterparts however, by its notably heavier weaponry and exclusive ability to use the Executioner and Infernus patterns.
Each and every Deimos Predator was Artificer-crafted by the finest machine-wrights of the great forge-complexes of Mars. The Deimos Predator Destructor and its variants haven't been constructed on a large scale, or at all, since the Age of Apostasy (You can thank Asshat McFucknugget for that) for the Chapters of the Space Marines. The Deimos Predator Destructor is the standard pattern of Deimos Predator, and is armed with a turret-mounted Autocannon known as a Predator Cannon and two sponson-mounted Heavy Bolters, one on each side. The sponson-mounted Heavy Bolters can be replaced with either Heavy Flamers or a twin-linked Lascannons (Turning it into a normal Predator Annihilator by function), depending on if the mission calls for close-range fighting or an enemy fielding a large number of armoured vehicles. The vehicle can also remove its sponson weapons entirely to reduce weight and increase speed, although this is rarely done for obvious reasons on bringing a tank with half its armaments on the battlefield.
The Deimos Predator can also be outfitted with a dozer blade, extra armor plating, a Hunter-Killer Missile Launcher, improved communications equipment, a pintle-mounted Storm Bolter, a searchlight, and smoke launchers. During the Great Crusade and subsequent Horus Heresy, when these vehicles were in service to the Space Marine Legions, they could also be equipped with an auxiliary drive system, armored ceramite plating, and even a Machine Spirit. Their pintle-mouted weaponry could include Combi-Bolters or other Combi-Weapons, a Heavy Flamer, a Heavy Bolter, or a Havoc Missile Launcher.
It is still used by Space Marines in the present timeline and still produced, although only by Mars and is considered a relic.
Executioner Pattern Predator
Much like the Leman Russ Executioner, this variant mounts a Plasma Destroyer, basically a Plasma cannon that fires in bursts, with the standard twin heavy bolter sponsons. More exotic variants swap out the Plasma Destroyer for a Heavy Conversion Beamer instead, granting them superior long-range firepower at the cost of an inability to fire while moving and greatly weakened attack capability at close range. It was known that each and every Deimos Predator was Artificer-crafted by the finest machine-wrights of the great forge-complexes of Mars and that the Predator Executioner just added several more layers of complexity in the design frame. Even in the Great Crusade these babies were a tough bitch to construct.
The Deimos Predator Executioner, as with all Predator tanks, can be armed with up to two sponson-mounted weapons including the aforementioned Heavy Bolters, Heavy Flamers, or Lascannons. The tank can be equipped with a variety of Pintle-mounted weaponry, including a Combi-Bolter or other Combi-Weapon, a Heavy Flamer, a Heavy Bolter, or a Havoc Missile Launcher. The vehicle can also be outfitted with a Hunter-Killer Missile Launcher, a dozer blade, an auxiliary drive system, extra armour plating, armoured ceramite plating, or an advanced Machine Spirit (Artificial Intelligence). All Deimos Predator Executioners are equipped with smoke launchers and a searchlight.
As with Mechanicus incompetence, the Deimos Predator Executioner is no longer manufactured on a large scale, or at all, for the Chapters of the Space Marines as the Mars Pattern Predator is now used almost exclusively by the Adeptus Astartes. As Plasma Weapons technology has been nearly lost to the Imperium in the late 41st Millennium, the Predator Executioner's main weapon, the Plasma Destroyer, is extremely rare and difficult to replace.
Infernus Pattern Predator
The Infernus pattern mounts heat-based weapons and is built for assaults. It can mount a Flamestorm cannon which replaces the Autocannon found on more conventional Predators. The Flamestorm cannon is a massive, vehicle-sized Flamer. The Predator Infernus was fielded in large numbers by the Space Marine Legions during the Great Crusade, although by the late 41st Millennium it has been mostly replaced in many Chapters with the more heavily armoured Land Raider Redeemer. For added anti-tank punch, the Infernus can replace the Flamestorm with a Magna-Melta cannon which is essentially a twin-linked Heavy Melta, which as you can imagine creates a hilarious vapor storm of rape and rage. The Deimos Predator Infernus, as with all Predator tanks, can be armed with up to two sponson-mounted weapons including Heavy Bolters, Heavy Flamers, or Lascannons. The tank can be equipped with a variety of Pintle-mounted weaponry, including a Combi-Bolter or other Combi-Weapon, a Heavy Flamer, a Heavy Bolter, or a Havoc Missile Launcher. The vehicle can also be outfitted with a Hunter-Killer Missile Launcher, a dozer blade, an auxiliary drive system, extra armour plating, armoured ceramite plating, or a Machine Spirit (Artificial Intelligence). All Deimos Predator Executioners are equipped with smoke launchers and a searchlight.
The Infernus pattern was hilariously a product of the Mechanicus being beaten at their own technology-hoarding game. Because the Blood Angels refused to share the pattern for the Baal Predator when they found it during the Great Crusade, the techpriests of Mars then came up with the Infernus Pattern. They made it so that it virtually surpassed the Baal in almost every regard, including being better armored and armed, a bit as a way of sneering at the Blood Angels. Which proves that sometimes, you just have to force the Mechanicus to work to get anything good from them.