W.T. (Weird Thing)
Wabash Cannonball
Wabash Cuddlewumps
Wabash Kissywumps
Wabba
Wabbit
Wabbly
Wackey Cat
Wacky
Wackywoo
Waddles
Wade
Wadsworth (after Henry Wadsworth Longfellow, american poet)
Wadworth (after the brewery in Devizes, Wiltshire, England)
Waffle
Waffles
Wag
Wag-A-Lot
Waggie
Waggler...