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.