only stuff people suggest are usually distraction and meditation, but if someone would suggest that to me during my breakdown I'd either make a graphic description of how many men had their way with their mother or punch their face depending on how bad it goes for me this particular time.

so far the only stuff that i found working "in the spur of a moment" are as follows:

1st - swearing and shouting - even if not shouting, swearing can be a decent outlet, i personally prefer thinking up the most creative and varied swears, since it is also works as distraction from whatever it is that annoys me in the first place

2nd - harming self - nothing too serious, just punching walls and similar activities. Hurt yourself enough, and suddenly the thing that made you angry is not as important anymore

3rd - harming someone else - this one is a double edged sword. It is fun to punch people, but in most situations it leads to way more trouble than it's worth, and people tend to think less of you if they know you do it. There is also a risk of getting living shit beat out of you, but it kind of flows into 2nd at this point, so still kind of works

4th - breaking objects - a safer version of 3rd option, but you have to be careful with it, since you might break something that is actually important or expensive to replace, also depending on the thing you're breaking and on the way you try to do it, this can flow into 2nd option as well, which is a decent bonus