An Imperial Knight Paladin excels in engagements, where its Chainsword and Shock Lance will make short work of most targets. It is also armed with a Battlecannon for long range support.
The Ordinatus Mars is a gigantic mobile weapon platform employed by the Adeptus Mechanicus. Its Sonic Disruption Cannon has huge range, and will destroy absolutely anything under multiple blast templates. It has Void Shields for protection, but will almost certainly be a priority target for the enemy.
A Capitol Imperialis is a gigantic mobile command centre, capable of transporting whole regiments of troops. It is slow but incredibly heavily armoured, and it is protected by several Void Shields. It doesn’t feature in any approved Epic Armageddon lists, but it can be found in the Space Marine 2nd Edition rules.
The Leviathan is an office block-sized vehicle with an impressive array of weaponry, Void Shield protection, and huge transport capacity. Its main armament, the Doomsday Cannon, has enormous range and will destroy most enemies in a single volley.
The Trojan Support Vehicle is an armoured tractor capable of towing heavy guns into position.
A Chaos Subjugator Titan is a close combat orientated War Engine that will stride at speed across the battlefield in order to rip enemy units of all sizes to shreads with its Hellclaws.