While plasma hasn't reached the same prominence on the battlefield as a weapon like EM projectile weapons or other energy weapons, they do make for an excellent support for those other weapons.

Such an example comes from plasma conductors, self-organized and structure plasma designed to conduct electricity for producing electromagnetism to accelerate projectiles in place of traditional materials. Plasma conductors have the advantage of not warping or falling apart from the sheer kinetic forces of propelling objects.

To the left is an example of a railgun configuration using plasma, while the right is an example of an electric launch version using the fourth state of matter.