R2 proves himself in battle. 3PO is created by Anakin Skywalker. R2 and 3PO meet. R2 and 3PO become involved in galactic affairs.
Both survive the Clone Wars. 3PO has his memory circuits wiped. They idle through the next few decades. They happen to be aboard the ship Darth Vader intercepts, the one carrying Princess Leia and the plans to the Death Star. Princess Leia hides these plans in R2. R2 and 3PO are officially drafted into the Rebel Alliance.
R2 frets. 3PO frets. R2 is nearly eaten by a giant swamp creature. 3PO is nearly obliterated in Cloud City. Both survive. 3PO becomes a storyteller.
R2 helps guide affairs all along. 3PO seems to be lost the whole time. R2 and 3PO make a unique pairing. They're separated countless times, seem entirely mismatched, imperiled more often than anyone else. Yet they survive. They survive the whole thing. And they're in the same position as always, when Luke Skywalker overcomes his father, Anakin, ends the threat of the Empire, of the Sith.
What do either have to do with the Force? Only what R2 understands functionally. Which is to say everything. He knows next to nothing, same as 3PO. And yet both seem to stumble into exactly the right circumstances. All the time.
They're pretty heroic. Forget everyone else. Follow only these two. The story remains the same.
These are the droids you're looking for.