This common name refers to only one order.
These are pretty much always called True Flies.
This incredibly diverse order holds tens of thousands of species. They are the "true flies" with two wings, and they have complete life cycles (larva to pupa to adult). Beyond that they have little in common.
The most important family is Chironomidae
, the midges. The craneflies of Tipulidae
and the related families may also be important, as may be several of the others in the right place and time.