Corellian Corvette, alias Blockade Runner, is the first ship seen in the first Star Wars movie... In the game world, it is widely used by rebellion and other factions also.
Victory-class Star Destroyer is another vessel not seen in movies. It is predecessor of Imperial Star Destroyer, is 900 m long and has seen it's best years during the old republic. Although it's too slow to be too effective in ship-to-ship -combat, it still excels in one area: It is still the largest ship able to enter a planet's atmosphere. Combined with it's heavy weaponry, this attribute makes it excellent ground assault craft.
Remember the opening scene of Babylon 5 (not the pilot, the actual series), where Narn fleet attacks a Centauri space station in Ragesh III I was sold the moment I saw that, as it made an immediate connection to my favourite PC game intro - Master of Orion 2.
Rebels sneaking towards landed Lambda -class shuttle
Scratchbuilt Lambda -class shuttle is being loaded, when the rebels attack