The Nebula-class freighter was a type of freighter that was in use during the Clone Wars. By 19 BBY, the pilot Trace Martez owned a heavily-modified Nebula-class freighter that she hoped to turn into a faster vessel which she named the Silver Angel.
Ahsoka Tano and Trace Martez working on the Silver Angel
The Nebula-class appears in the seventh season of Star Wars: The Clone Wars animated series.