Protocol Droid
Often seen with C-3PO.
In “The Empire Strikes Back,” R2-D2 is present when Luke Skywalker failed to sneak up on Boba Fett in Cloud City, saving Luke from getting shot by Boba Fett’s EE-3 blaster shots by delaying Skywalker’s movements.
Even before this, R2-D2 saved Luke’s life in the “Holiday Special” cartoon, “The Story of the Faithful Wookiee,” where R2 manages to intercept a message between Boba Fett and Darth Vader. R2 then relays the message via C-3PO that Fett is working for the Empire before he could capture Skywalker and the rebels.
More about R2 in The Fetts and the Droids: Artificial Intelligence in Fett Lore by Mosh Babilonia.