I'm assuming you mean different animations? and old way I went about with it, was to have 5 different attack animations on the player character, then have this script run in the global events scripts whenever a character took damage, changing the attack animation to a random one of the five.. This unfortunately also plays the animation for some reason, which eventually made me stop using it, but you can use the script as an example of one way to go about making the boring normal attack animation a bit more interesting.
$attackanim = random(1, 5);
if $attackanim == 1 then
override_animation(player, "attack", "attack");
elseif $attackanim == 2 then
override_animation(player, "attack", "attack2");
elseif $attackanim == 3 then
override_animation(player, "attack", "attack3");
elseif $attackanim == 4 then
override_animation(player, "attack", "attack4");
elseif $attackanim == 5 then
override_animation(player, "attack", "attack5");
end;