There is a bullying forum at:
I have introduced Personality Types into the discussion. It seems that all sorts can bully or be bullied.
However, the worst ones (my view) are ESTJ and ESFJ. The INXP is less likely to notice until the bullying gets very severe. Other bullying types identified have been ENTJ and ENFJ and even ISFJ (by Poison Pen) and INTJ (by secret underhand conniving).
So far ISTJ and INFJ have been moderately OK, although I suspect at least one ISFJ.
If the ESTP decided to bully (and they may do it using agents) they are likely to be very dangerous. I supect two of these using a ESFJ and ISFJ to do the dirty work on their behalf.