R. Fletcher was a Starfleet officer in the 23rd century.

In 2385, he was a captain assigned to Starfleet Academy's Starfleet Training Command. His office, located on the second level of a building, was in room #211. His rank, name, and office were listed on a directory placard. (Star Trek II: The Wrath of Khan, set artwork)

This character was only mentioned in writing.
He was named after Robert Fletcher. The placard was sold on It's A Wrap! sale and auction for US$31.99. [1]