What is non-CDL?

Any licence which isn't a CDL licence. However, there's a certain context you're looking for, so let me explain it in that context:

Commercial vehicles are regulated by the Federal Motor Carrier Safety Administration. However, there are vehicles which are exempt from federal motor carrier regulations. These include:

• Recreational vehicles and motorhomes
• Registered farm vehicles, not used on a for-hire basis, and operated by the farmer, their immediate family, or direct employees of that farmer in support of the activities of that farm
• Firefighting and first response vehicles, when operated for that specific duty
• Military vehicles operated by military personnel in the course of military activities.

States maintain jurisdiction over licencing requirements of these vehicles (except for military vehicles), and set their own regulations for what the licencing requirements are. Special classes of drivers licences may exist for them, or the state may offer non-CDL equivalents to the Class A and Class B CDL.