Oddball is a term the hobby has adopted to catagorize cards that were not produced in small quantities by companies that do not produce cards as their single business enitity and often only release the cards REGIONALLY vs NATIONALLY.

Over the course of 40 plus years there have been literally hundreds of cards produced by off brand companies. By off brand, I am referring to companies that either don't typically produce sports cards. Companies like Post Cereal or small local companies that produce cards for a home town team or release cards in a REGIONAL area. Companies that didn't produce large quantities of cards that were released NATIONALLY like Topps or Fleer are typically considered odd ball cards. Being odd ball can make these cards quite scarce and often quite valuable.