The only other countermeasures I can think of are electronic (deny control of the drone, or its ability to navigate) or some sort of directed energy (shoot them down with l@sers).
As previously posted - point and shoot, no cost apart from the electricity., already starting to be deployed by the US army.
https://www.defensenews.com/land/202...laser-weapons/
Army readies to deliver first set of Strykers with 50-kilowatt laser weapons