Part of the fun of magical "mines" from the great war is that DFRPG already encourages the GM to ignore point values for monsters and, by extension, to "foe tech." And there's no mechanical power-building system, so we have permission to let our imagination go wild. Here's a quick brainstorm of a few magical traps that might be deployed in a war:
- Some sort of anti-stealth tech. Perhaps you and your unit get lit up with faerie fire. Or a flare fires into the sky, lighting up the entire battlefield.
- Maybe something interesting with the Pull spell from GURPS Magic. Nearby beings are pulled to a central point. Maybe there's a pit at the center. Or an evil rune. Or a poison cloud.
- A mana sensor of some sort. Might work like the faerie fire effect but only on mages.
- Similarly, dispel magic mines or fields that negate ongoing magical effects.