OSHA only requires specific contents in a first aid kit for specific industries, such as logging. Aside from that, their regulation reads:
In the absence of an infirmary, clinic, or hospital in near proximity to the workplace which is used for the treatment of all injured employees, a person or persons shall be adequately trained to render first aid. Adequate first aid supplies shall be readily available.
ANSI has a recommended list of first aid supplies, though it is not a legal requirement. A summary of this standard is included in the document attached here.
Basically, your company needs to determine what specifically it wants/needs based on the hazards of your working environment. There are a few different ways to get an idea of what is needed. First, look at your records of what is being restocked in the kits. Second, talk to the employees and managers to figure out what supplies they like and do not like. They might also have supplies in mind that you do not have. Doing these two things gives a pretty good idea of what to have in the kits for everyday use. You should also look at the hazards of the work area to determine what harm could happen and stock supplies for those issues as well.
*Unless specific citations are shown, all answers are based on interpretations provided by authorized officials. As such, all information is deemed reliable, but not guaranteed.