There is a group with the Keirsey allocation of **FJ which I call the Fraudians, because they believe in unconscious Feeling world of the repressed egotistic (Horseman ESFJ) cocaine habitee called Sigmund Freud, plus the instant judgement to protect their vested interests the *S*J Guardians. They are dangerous to cross because they do not act by reason and logic, but engage their feelings.
ENFJ "Beaver" (the original allocation of "Wolf" was re-allocated to ENTJ) has an external agenda and anybody he does not feel that fits it with it, he plots against. Beware of retired teachers with not enough to beaver about and do.
ESFJ "Horseman" and various variants like "Camels" and "Unicorns" are the most dangerous simple character types around. They act for personal self interest rather than an agenda. The agenda can be invented after they have acted.
ISFJ "Mouse". Ostensibly these rodents appear harmless, but they can contaminate anything with their poison pen and tongue. They act out of self interest.
INFJ "Skylark". One of the most engaging personalities around. I have not known them cause any trouble, but their problems seem intractable.
The latter two will not instigate fraud, but may turn a blind eye, or even support the fraudster out of loyalty or self interest: the mousy wife and the horse thief.
All character types have variants, like the dirty snivelling Rat (ISFJ/ISTJ).