The rebelion launched some fleet actions in the EU. But yeah they were mostly ambushes when Rebel Intel figured out where an Imperial fleet was going, raids on isolated detachments and outposts, fighting retreats if the Empire managed to locate the main rebel fleet or diversions to buy time for bases to be evaced.
It will be interesting to see if the Rebels Cartoon shows the battle mentioned in the ANH opening text and what form it will take if they do include it. The EU made it the first stage of the Battle of Toprawa and showed it as a massive fighter raid but I'm hoping if Rebels covers it the battle will be a fleet action.