Yes there are conversions available for most light trucks and SUV’s. Not all conversions are equal, conversions that have been tested and certified will have a CARB certificate that proves that it is approved for the engine and will not violate any clean air standards that the vehicle must meet.
Ford, Chevy, and Dodge all offer CNG trucks new as well.
For heavy duty applications Cummins makes several natural gas engines and conversions are available for Isuzu and others. There are many other engine manufactures making natural gas engines and conversions as well.