If your employer is not governmental, it is extremely unlikely that any plan to which it contributes would be a governmental plan. The only exceptions would be plans that primarily cover employees of governmental employers, but also cover certain entities with a strong connection to a governmental entity (e.g., a union representing governmental employees). Announcement 2011-78.
If the employer contributing to the plan is an international organization which is exempt from taxation by reason of the International Organizations Immunities Act (59 Stat. 669), it is considered governmental. This basically covers entities like the World Bank, of which the United States and other governments are members.
The Railroad Retirement program provides benefits to individuals who have spent a substantial portion of their career in railroad employment. The plan is treated as a governmental plan. But unless you have specifically been told that you are covered by the Railroad Retirement Act, this would not describe your plan.
There is no central list of governmental plans. If there is any doubt whether your plan is a governmental plan, you'd have to ask your employer. If your employer says your plan is not governmental, and you want to challenge that, you'd have to look to Announcement 2011-78 for guidance.