There are websites that list the categories (grasmick.com for example). It is pointless to list any here; her current education and experience will dictate her possible carreer path. since you did not start out this thread with "my girlfriend is a ..., does she qualify for TN", I'm assuming she doesn't.
Typically, one is already educated or experienced in a professional field before investigating TN. If not, then may i suggest that marrying her would be a quicker and simpler alternative for her than spending the next 2-5 years gaining the required education to get TN.