Huey, Dewey and Louie

noun[plural only]2

1. •
   Three hypothetical customers, user personas, or similar constructs.
2. •
   (slang) Three twos; a three of a kind of twos.

   • Gentleman Johnny's Huey, Dewey and Louie are the next highest cards visible. The three twos look puny against light-fingered Tucker's kings, but Johnny's still in the pot. — 2011