Conflict brings change, and change brings opportunity. Many in the galaxy are unsatisfied with the status quo—especially as it exists under Palpatine's rule. The Alliance's war against the Empire provides an extraordinary chance to topple the current order and bring about more desirable changes. Whether those changes are oriented toward reestablishing the Republic as it was or installing a new structure altogether depends on the individual's frame of mind.

Many who seek such change are genuinely altruistic in their goals. They recognize the evil of the Empire and the suffering it brings. They're motivated to end this evil, and the Rebellion's organization and resources offer the best possibility of accomplishing their goal. Whether they join the Rebellion simply because they were made aware of Imperial atrocities and destructive policies, or because they and their loved ones have been directly victimized by the Empire, is for the players to decide.

Others have less idealistic, perhaps even selfish, goals. Current policies might cut into their ability to make a profit in their chosen vocation or damage the business they choose to run. Perhaps a character has run afoul of Imperial authorities one too many times, and he sees an alliance with the Rebellion as his best chance of escaping the less-than-tender mercies of the Empire's justice. Some PCs may simply see a chance to grab some credits and valuable assets while helping to strike against the Empire's forces.

A technician or engineer could have had his designs rejected by Imperial agents, and the Alliance is providing him a chance to vindicate his work. A politician or political operative might have been ousted when the current regime took power; the Rebellion provides an opportunity to reclaim a sense of purpose and authority. A pilot deemed unfit for service and rejected by the Imperial Academy would consider flying for the Alliance a chance to prove his worth at the controls of a starfighter.

The Accidental Rebel

The vast majority of the sentient beings of the galaxy have no desire to join the Alliance or serve in the Rebellion. They may not be ardent supporters of the Empire, but this doesn't mean they are willing to drop everything in their lives to go blasting away at hordes of stormtroopers or weaving a dilapidated starship through swarms of TIE fighters. They would rather go about their business and live their lives, hopefully out of the way of any battles or other trouble.
H.I.V.E. (Heuristic Intelligence Vector Engineer)

Droid Rights

This character fights for the rights of Droids and that they be recognized by the galactic community as sentient beings.

Support
Individually, the lone agents of the Alliance don't stand a chance against the combined might of the Galactic Empire. Only by working together can they hope to achieve a victory in this civil war. This PC is devoted to helping fellow Rebels fulfill their Duties by providing whatever assistance they need. Although he might not get the same amount of reward or recognition as the people he is helping, the PC has many more opportunities than his fellows to fulfill his Duty to the Rebellion.

A bipedal droid that looked like it might have, at one point, been a protocol droid of some kind. he droid had a variety of plating missing and looked to consist of parts that might have been new a few decades prior.