When you get a assist it counts as a kill, which can confuse people that you are really good.

match start and end would be nice

Its a Rotating Gamemode, a lot of people will play it during its stay, and a lot of Nice Clips will be made, Highlights would make it faster and easier to get nice clips

Sometimes getting a steam achievement in any game can result in some funny stuff. I think sometimes it'd be neat to clip it.

goals, fouls, goalkeepers highlights

This would benefit mtga players a lot allowing them to capture highlights. As for powerful card placed, there is an event for this that triggers a flare in the dynamic music. The "someone says nice trigger" would go off whenever someone says nice ...

Kills, Death. Knocked, Win, Lose, Defuser plant, Defuser destroyed (i guess that counts as win/lose)

It could work where it starts/marks a capture at the start of a run and stops/marks at the end

Capture when you kill or die to a raid boss/encounter(or simply the full raid encounter), good for highlights and improving gameplay to see mistakes after a wipe.