One of the earliest products to be sold through Master Mortimer's Mercantile was writing quills and walnut ink. He had discovered his source for ink on a trip to the local neighborhood of Sleepy Hollow while he was living in upstate New York. 

As his brand, his stores, and his suppliers expanded, his options for ink would grow; he would eventually diversify his line of inks to include squid and octopus, as well as iron gall ink.

He had also sourced the feathers from the wings and tails of wild American turkeys. While goose feathers were commonly used amongst the mundane citizens of the community, he preferred promoting the wild stripes of these most intelligent birds to his fellow magical members. These quills would later come to be associated directly with Master Mortimer's Magical Mercantile across the country.