Einstein's relativity theory, Aristotle's philosophy, theoretical mathematics are all very heavy on Ti use.
What else..hmm..how could I say this in ENFP tongue...I dont know man..i feel and i feel not its useful..i mean useless..hehehe
Well...Jung's typology was Ti work as it required careful inquiry into human nature and careful organization of the insights...
What else....uhh no not really you cant do anything its only thinking after all...just do what feels right it will always work out for you. Dont think too much, it makes your head hurt.