You could always be an INTJ type 6, but then again maybe not. I'll ask a couple of questions (or you could do a questionaire and more people would respond). If you choose to answer my questions, be descriptive (but don't write a textbook). The more I can key into your motivations, the easier it will be to identify your functions.
1) Describe something that you strongly dislike/hate. It could be anything from a food, to a person, to societal trait (whatever). Why do you hate it?
2) Was there ever a point in time where you acted atypical of yourself? Describe it.
3) What type of people do you tend to surround yourself with? What type of people do you tend to avoid? Why?
4) What are the type of people that you admire/aspire to be like (if you don't have any just list traits that would make for your ideal self). Examples are welcome.
5) Describe how you use Ni in your daily life.
Depending on how you answer I may ask more...
I'm not entirely solid on being INTJ - I could see INTP, ISTJ, ENTJ, INFJ (unlikely) or maybe something else - so I'm responding here too.
1) People who are lazy and don't know how to work. It really bothers me when people only want to fool around
when they're supposed to be doing productive things. I have nothing against fun, but extreme inefficiency really grinds my gears.
2) One time, I tried being social. It was horrible. I went to a few house parties and they were really boring. People tried socializing with me, but it wasn't very interesting. It was a waste of time and I didn't learn anything interesting other than solidifying my idea that I'm not made for parties or social situations. The worst part was probably when I was playing a speed-based card game with a girl and someone asked if we were dating. Nope, definitely not. He then suggested that we should. I had no interest in her, so that irritated me. I didn't know how to respond since it was such a weird remark.
3) I like surrounding myself with driven and intelligent people who want to be good at the things they do. Sometimes I'm not too terribly motivated, so it's always good to have people who can push me. I tend to avoid bubbly people - they tire me out
so quickly - along with willfully ignorant people and those who are complacent. I don't know any INFJs, but I have a hunch I would greatly enjoy being around them.
4) I'd like to be a more perfect version of myself, notably with better time management skills and more ambition. My goals are all lofty and not very specific: Get a job in chemical engineering which satisfies my need to solve problems and pays well; find a woman to marry and raise a family with; grow in self control so that I can play video games again - I easily get lost in the depths of figuring things out and optimizing, and lose track of time.... Maybe this is too far off-topic from the question, but I think I'd probably be satisfied taking organic chemistry exams for the rest of my life. I also really like programming, although I have no reasons to do so currently. I admire masterminded characters who have secretive plans and know they'll succeed, such as Gandalf (LotR), Artemis Fowl (Artemis Fowl), Telamont Tanthul (from D&D... Google does a reasonable job), and Kaname Kuran (Vampire Knight).
5) I have a hard time understanding most of the cognitive functions. Maybe I just haven't tried hard enough, but I honestly have no idea how I think in terms of cognitive functions.