At this page I try to list all known companys that produce discs for the game of ultimate (even if the discs are not officially approved by the UPA or WFDF).
Discraft – Inventor of the „Ultrastar“ – USA
Eurodisc – First european Ultimate Disc – Germany, Europe
Innova – Worlds biggest Golf Disc producer – USA
Wham-O – Inventor of the Original Frisbee – USA
Daredevail Discs – – Canada
Yikun Sports – UltiPro and other discs – China
Links will follow, help me if you now of more producers.