Lighting fixtures or luminaires, are required to be "Listed". You could manufacturer and sell them with out the UL Listing, but if there was a fire, shock or electrocution, you would be liable.
Here is the requirement in the NEC
410.6 Listing Required. All luminaires, lampholders, and
retrofit kits shall be listed.
Listed. Equipment, materials, or services included in a list
published by an organization that is acceptable to the authority
having jurisdiction and concerned with evaluation of products
or services, that maintains periodic inspection of production of
listed equipment or materials or periodic evaluation of services,
and whose listing states that either the equipment, material, or
service meets appropriate designated standards or has been
tested and found suitable for a specified purpose. (CMP-1)
Informational Note: The means for identifying listed equipment
may vary for each organization concerned with product evaluation,
some of which do not recognize equipment as listed unless
it is also labeled. Use of the system employed by the listing
organization allows the authority having jurisdiction to identify a
listed product.
UL (UL.com) is the most well known of product evaluation organizations, but there are others that may be less expensive to get your listing as a luminaire manufacturer.
As we are not allowed to assist DIYers, I am pointing you to the requirements so you can avoid any liability.
And is some installations, luminaires are inspected as part of the electrical permit, and a non listed luminare would not be allowed.
