of course, the Brabham BT46B 'fan car'- smashed everything silly for 1 race then was promptly banned
those sort of fans are currently covered under the 'moveable aerodynamic devices ban (apart from DRS). but say the FIA provides standardised drop-in fan(s) with the exact same maximum cfm rating (like the way IRL engines have control pop-off valves attached), and the whole DRS thing would likely become redundant.