Opening (OP) Cel, Ending Cel

These are the cels that you find in the opening of the show, most shows have 1 opening that is animated per season and then is just reused for every episode. It is the same for End credits only one set of cels is made for each season.   So these cels are generally the most sought after as most fans of the show find them easily recognizable.  They also tend to be super pricey as well, so watch out for fakes and reproductions being sold as the real thing!