What are we gambling for, you ask? Nothing all that valuable. Just your life!
~ Oogie Boogie

Gamblers are villains who live on gambling, or enjoy gambling. Sometimes, they don't just gamble with money, but also with people's lives.

These kinds of villains tend to be very chaotic, unreliable, temperamental, and capricious, since they hold allegiance to no one and tend to trust luck more than sheer power/strength.