The capability of consumer level drones are amazing these days and many of the larger ones can carry payloads of around 1+ kilos. Given the speed and viewable target accuracy they would seem to make ideal smart bomb platforms for precision targeting of things you want to cripple or destroy at a distance.
Why are no guerrilla armies doing this? A pound of C4 put in just the right place could do some damage.
As the others have said, just wait. Organized terrorists groups get hit back after they attack so they’ll be a little careful to make sure the technology works right, they don’t want to get droned themselves in retaliation for a failed attack. For the lone operators out there the problem remains the same for them, access to high explosives and the technology to detonate whatever explosives they have successfully. Unfortunately that’s getting easier to do.