Actually, Electrocutor is very helpful against various FGs:
Chaos Lord's Druids, Demons, and Werewolves
Dark Matter's Gravity Nymphs, Chargers, and Otyughs
Decay's Pests, if he steals a Quantum Tower, to keep them from burrowing
Destiny's Druids, Demons, and Fate Eggs
Dream Catcher's Butterfly Effect and Physalias
Elidnis' Forest Spectres, Puffer Fish, and Ulitharids
Eternal Phoenix's Phoenixes (if you can keep it from getting exploded)
Ferox's Rays of Light and Leaf Dragons
Fire Queen's FFQs and flown weapons
Gemini's momentum
Graviton's momentum, Firemasters, and Otyughs
Hermes' Destroyers and Spectres
Incarnate's Retrovirii, Bloodsuckers, and Vampires
Miracle's Pegasi, FFQs, and Leaf Dragons
Morte's Retrovirii, Rays of Light, and Condors
Neptune's Arctic Octopi
Obliterator's Shriekers and momentum
Octane's flown Eagle's Eyes
Osiris' Pharaohs, Scarabs, and momentum
Paradox's Rays of Light and Deja Vus
Rainbow's everything, if you can hang on to it
Scorpio's Puffer Fish, Physalias, Ulitharids, and Octopi
Seism's Shriekers, Antlions, and Gemfinders
Divine Glory and Decay are really the ONLY FGs that aren't crippled by the lobotomize effect - a lot of anti-FG rainbows pack Mind Flayers as an alternative to Electrocutor, if you'd rather. I have been considering adding a few to my deck.