PlaidCloud expressions and filters provide use of most non-administrative PostGIS methods. PostGIS methods are accessed by prefixing the standard method name with
ST_SetEffectiveArea(geometry geomA, float threshold = 0, integer set_area = 1);
func.ST_SetEffectiveArea(geometry geomA, float threshold = 0, integer set_area = 1)
PostGIS Official Documentation for this method can be found here.
Additional capabilities and usage examples can be found in the PostGIS documentation.