Xbox's new policy — say goodbye to unofficial accessories from November thanks to error '0x82d60002'
(www.windowscentral.com)
I assume he meant EVGA. They're a hardware company that used to manufacture graphics cards designed by Nvidia but exited the GPU market because of unfavorable contract conditions eating into their profit margins.
Plenty of other third-party manufacturers exist like Sapphire, XFX, PowerColor, Zotac, ASRock, Inno3D, Colorful, MSI and ASUS.
As for the main companies that design (and also manufacture) GPU's: AMD, Nvidia and more recently Intel.