In Solo: A Star Wars Story,

Han and Chewbacca delivered two cases of coaxium over to Enfys Nest, who stated that they were most valuable in funding "the Rebellion".

According to the Wookieepedia sources, the event took place around 10 BBY, but the Rebel Alliance was founded as late as in 2 BBY. Was the Alliance actually established earlier, after all, or did she refer to some other group of freedom fighters (unlikely!)?