You mean these functions that get the current value of the parameter?
GetStaticParameterValues
GetFontParameterValue
GetScalarParameterValue
GetStaticComponentMaskParameterValue
GetStaticSwitchParameterValue
GetTextureParameterOverrideValue
GetTextureParameterValue
GetVectorParameterValue
Or do you want to get a list of all the FName ParameterNames a MaterialInstance has?
In this case I think you’ll have to manually access them like this:
MaterialInstance->ScalarParameterValues[Index].ParameterName