Not sure I am following your question, so I apologize if I missed the point.
For HVAC, I brought along some ASHRAE (55, 62, 90), IMC (2006), NFPA (92) and ARI (550). I don't think they were all necessary, but I already had them from my job and played it safe. I felt there were no suprise questions that I was unprepared for with these.
I would highly recommend the ASHRAE codes for HVAC. It never hurts to have a copy of IMC either.
I almost never use ASME/ANSI codes, although there are a ton mentioned in our specifications. Maybe I was lucky :dunno:
