Rat names
Rats Domino
Ratso
Rat-ta-tat
Ratticus Finch
Rattus
Ratty
Ratty Arbuckle
Raven
Razzle (Raz for short)
Reese
Reeses
Reggie (nicknames: Reggie Weggie, Regster, Reginal)
Remy
Revlon
Rex
Rezin
Ricky
Riddick
Riff Raff
Rigby
Rimmer
Ringo
Riso
Rizzo
Robbie
Roberto
Robin ("Ratnick")
Rodney
Romeo
Ronan
Ronnie
Roo
Rosey
Rosie
Ross
R.O.U.S. for Rodent Of Unusual Size)
Rua
Ruby
Rufus
Salty
Sam
Sammy
Samule (Sammy for Short)
Samwise Gamgee (Sam for short)
Sandino
Sandy White Beans (Sandy Beans or Sandy for short)
Satsuki (Sukie for short)
Scabbers
Scamper
Scruffes
Scruffles
Scully
Scuni
Sebastian
Seifer (pronounced Sigh-fur)
Serenity
Seymour
Shadow
Shakespeare
Shanon
Sheila
Silk
Silversides
Simon
Sinclair
Skweekers
Slam
Slate
Sleeps
Smoky
Smudge
Smugey
Smurfy
Snicker
Snickers
Sniff Mister
Snoopy
Snowball
Snowflake
Snuggles
Socrates
Sophie