I sort of came up with these myself, of course being inspired by practice.
Ni - Eccentric, odd connections to reality, weird and dry humor (lack of humanistic substance?), oblivious, overly imaginative, things going on in our head are quite undefinable. Whims of genius that may or may not be realized. Inner world (alien planet).
Te - "That's just how things are" (here) sense of logic, alters definitions in logic to make it more directly fun and placeable upon occurrences with people. To be quite playful with reason.
Si - "Ok. Stop for a minute. What's really going on? Why am I out of place now?"
Fe - Events here may prove worthy, even if I become pushed or uncomfortable. Hopefully there will be meaningful organization mediated and not so much chaos.
I didn't get to finish with the other 4 functions, just sticking with the "mental" part.
Share your examples or definitions of the functions for any personality (even though this is an NT board.) I'd like to hear some examples for ENTP preferably, because I think it's cool how Ti is their creative function and they are out to be open minded. I want to know how one can come up with such invention by Ti being supportive.