Answer: The "Sus 2" chord is a triad in which the third has been replaced by a second, such as C, D, G instead of C, E, G. It's just a sound. It's nice. If it had any function at all it would be followed by a B, D, G, because the second would give the impression of wanted to resolve outward to a third, and that normally is done by moving the lower tone down a step.

The "2nd chord," to the extent there really is such a thing, is a chord in which a second has been added to the normal triad, for example, C, D, E, G. It differs from the Sus 2 in that the third, E, is present. It's pretty, too.

A "9th" chord is an extended version of a 7th chord: chords like the 9th, 11th, and 13th are basically 7th chords with some extra sprinkles on top for color. Extended chords will generally include the 7th, plus the added 9th or whatever.

A "m2" chord would, by extension of the above principle, be a triad that also included a m2 above the root: C, Db, E, G. You could say it exists, but it's not likely to do much for you.

Personally I don't see the 2nd, 9th, 11th, 13th as chords in the functional sense, though I know that having those terms handy is good for communication. To me these are just sound-effects: sonorities created by adding a few non-chord tones to a functional chord; they don't change the direction or musical meaning of the underlying harmony. But that's just me. I am no jazz expert and cannot convincingly pretend to be one; so I continue to think in terms of functional harmony. Everything else is color, which can be very good color but doesn't have very much harmonic theory behind it.