The EDD file will show a list of all potential actuators in the model if you set the first input field to Verbose for the following Output:EnergyManagementSystem object in your IDF before running a simulation:

Output:EnergyManagementSystem,
    Verbose,    ! Actuator Availability Dictionary Reporting
    Verbose,    ! Internal Variable Availability Dictionary Reporting
    ErrorsOnly; ! EnergyPlus Runtime Language Debug Output Level

After running a simulation, EnergyPlus will generate the EDD, where you should find the following list of potential EnergyManagementSystem:Actuator options for fans:

• Fan Air Mass Flow Rate - this is likely the actuator that you want to use to change fan speed level
• Fan Pressure Rise
• Fan Total Efficiency

Besides the EDD, you can also find lists of potential EMS Actuators in the EMS Application Guide. Here is the section for fans.