What attacks/techniques have you witnesed score the most points (or knock out opponents in full contact)most often in competition fightin?

What kind of competition?

any fighting competition,any style full or semi contact

Sorry, you do need to be a bit more specific. Are you talking about boxing? TKD? Obviously, they will have different attacks that score more. Even in boxing, jabs probably get more points, but hooks or overhand strikes have more KO's.

In TKD, kicks will score more points and have more KO's. Really depends on what you mean.

sorry if this isnt clear i thot it was the whole point in this post is to discover which attaks score most in any system...ie if u do tkd tell me which technique u see score most in tkd competitions if u do boxing tell be what punch/combo scores most often

Right, I think I see what you're getting at.

I used to do semi contact karate and the technique that cleary scored more than any other was the reverse punch.

Lunge punches and backfists seem to rarely score, the same with front and side kicks.

Round kicks to the body were impotent too for that matter, whereas round kicks to the head would often score. The same with reverse round kicks to the head, but not body.

All of the above means pretty much nothing to anyone outside of my old style and the tournaments they entered, as different styles have a different emphasis.
So it's not just about which art it's which style, of which art and very often which association, of which style, of which art.

The kick that I've seen score most in TKD must be a roundhouse to the body, followed by back kick, roundhouse to the head, reverse turning kick to the head and axe kick.

In boxing, it is the straight right (or left, if you are a southpaw.)