Only 2 mechs mentioned in the book exist in the game so far. I posted pictures of them. PGI is hoping to release every mech known to man so all of these will be coming at some point :D
Mentioned in the book but no detail
Listed in the glossary and used in the book.
This 80-ton assault 'Mech moves at a maximum speed of about 64.8 kph, and is the only one of its class with jump capability (120 meters maximum). The Victor mounts an autocannon in its right arm, two medium lasers in the left arm, and an SRM 4 in its center torso. In battle, the Victor is often able to throw its opponents off guard, as they do not expect to find a heavy 'Mech with jump capability.
The 80-ton Zeus is the pride of House Steiner. whose designers created it as a heavy 'Mech capable of performing hit-and-run tactics. It mounts an LRM in the right arm, a large laser and medium laser in the left torso, a medium laser in the center torso, and an autocannon in the left arm. The Mech's top speed is 64.8 kph. Its excellent armor, especially around the chest and legs, allow it to withstand all but the heaviest fire. Its strong, heavily armored legs make the Zeus a feared kicker, and a bludgeon feature on its left arm gives it a mighty punch.
A formidable assault ‘Mech, the BattleMaster weighs 85 tons and has a maximum speed of 64.8 kph. The firepower that the BattleMaster can generate in one volley is staggering and more than deadly at close range. Its main fire weapon is its right-arm PPC, and its three right-torso and three left-torso medium lasers provide close support fire. Of the six lasers, two are mounted on the 'Mech's right and left rear, making it one of the few models equipped with rear firing weapons. An SRM 6 and two machine guns complete the BattleMaster's weaponry.
The Dragon is a well-armed 'Mech whose top speed of 86.4 kph makes it one of the fastest of the heavies. Armed with 24 rounds for its LRM and a whopping 40 rounds for its autocannon, the Dragon can carry on sustained battles without reloading. Even if ammo does run low, the 'Mech's left-arm and left-torso medium lasers ensure that it has other weapons to fire.
Because of its size and weaponry, the 70-ton heavy 'Mech War-hammer is one of the most dangerous and powerful on the battlefield. It mounts PPCs on both right and left arms, an SRM on the right torso, and a medium and small laser and a machine gun on each side of its torso. These give it the sheer firepower needed by a first-line fighter. The special searchlight mounted on the 'Mech's left torso ties in with its tracking system. Able to function either as a light or as part of the targeting system, this feature makes the WarHammer a formidable night-fighter. The Mech's top speed is 64.8 kph.
JagerMech: This 65-ton 'Mech mounts two light and two medium autocannon and two medium lasers. Its top speed is 64.8 kph. Crusader: A heavy BattleMech, weighing 65 tons, with a top speed of 64.8 kph. It is heavily armed even for a 'Mech, mounting a laser, heavy machine gun, and massed LRM batteries in each arm, and SRMs on each leg. The Crusader is capable of delivering a full spread of 42 missiles at optimum 160-180 meter range, with the potential of crippling or destroying even the mighty BattleMaster
The Thunderbolt is a 65-ton heavy 'Mech, and is one of the best-armed 'Mechs in existence. Its arm-mounted large laser packs a powerful punch. Combined with its three left-torso-mounted medium lasers and the SRM 2 mounted on its right torso, the 'Mech has ample firepower at long and medium ranges. For close combat, it mounts a torso-mounted SRM 2 and two left-arm machine guns. Vindicator:
The Vindicator is a 45-ton medium 'Mech that is not particularly fast (top speed 64.8 kph) for its size. One of the most common 'Mechs among the House Liao forces, the 'Mech mounts an LRM in the left torso, a PPC in its right arm, a small laser in its left arm, and a medium laser that bulges from the left side of the 'Mech's head.
A 'Mech design seen only among the forces of House Davion, the Valkyrie is a highly regarded light 'Mech. Its six tons of armor, top speed of 86.4 kph, and 150-meter jump capacity allow it to outmaneuver heavier units in battle and to absorb a fair amount of damage. Its left-torso LRM is unusual in a light ‘Mech, making it a potentially tough opponent at long range. At close range, its right-arm medium laser and super jump capacity can be a potent mix. Though no match for a medium or heavy ‘Mech in one-to-one combat, the Valkyrie is effective when part of a lance.