Someone with a passion for something. Whether it be music, writing, cars, dancing, sailing. By having a passion for something you show that there is an activity that you love and that you commit to. You also, indirectly, demonstrate that you are independent, have your own space, and do not need to rely on her attention all the time in order to feel satisfied.
A person who will respect their values and give them space. If she says, "I like bird watching. There's something incredibly relaxing about it and I love seeing birds take off." Don't reply with "but what's the point? It doesn't even achieve anything." I can't speak for all INFPs but I tend to be very quiet yet fiercely protective of my values and those who are close to me. Never verbally attack someone important to her; she may react as though you have attacked her directly. Also, if she shares something with you or tells you what is important to her, listen. Concepts like identity and authenticity are important to the girl, a guy who is accepting or showing a willingness to learn is a must.
I understand that NTs (huuuge generalisation, don't shoot me) may dislike wishy-washy stuff (why are you reacting to this so personally/ yeesh, it's just a
song/ yeah but dragons don't exist in real life) but just be patient. Of course there are limits to much one responds emotionally in a given situation but I'm sure you can judge for yourself.
General:
Guys who can cook
Guys with a sense of identity
Guys who are not overly emotional but at the same time know how demonstrate an understanding of "feelings"
Mental strength
Guys who don't let small things affect them
Wit/sense of humour