Sabastian
Saber
Sake
Salem
Sam
Sambuca
Samson
Samuel
Sarge
Satchmo
Savoy
Sawyer
Scamper
Scardy
Schnapps
Schwartz
Scooby
Scooter
Scotch
Scout
Scrappy
Scrubby
Scruffy
Scud
Sean
Semper Fi
Sergeant
Sergei
Serpico
Seuss
Seven
Seymour
Shaggy
Shaker
Shakespeare
Shamus
Shane
Sharpe
Shaw
Sheik
Shelby
Sheldon
Shep
Sheriff
Sherman
Shiloh
Shonen
Shorty
Shotzie
Sidney
Sigmund
Silver
Simon
Sire
Skank
Skeeter
Skipper
Slater
Sleepy
Slug
Smitty
Smokey
Snickers
Snooper
Snoopy
Snuffy
Socks
Socrates
Soda
Soldier
Solo
Solomon
Sonny
Sony
Sooner
Soprano
Soren
Soto
Sox
Spago
Spalding
Spam
Spanky
Sparky
Spazz
Speedy
Spencer
Spider
Spike
Sport
Sportster
Spud
Spunky
Squall
Stain
Stanley
Statler
Stavros
Stetson
Steve
Stewart
Sticky
Sting
Stinker
Stollen
Stray
Strider
Stubby
Strudel
Stryker
Styles
Sudz
Sully
Sultan
Sushi
Swamp
Switchblade
Syrus
Syther
Syxx