There are different styles and techniques of realtime VFX'es. Cartoonish, stylized, realistic. 

Every texture is procedurally generated with Substance Designer. This allows to rapidly iterate during polishing or modifying textures from one to another. So scaling project content is fast and easy. 

Implemented in Unitys Particle System. 

Flashes are usable almost everywhere especially in explosions. 

Various techniques from simple randomize of flame chunks to custom shader animations, like displace and temperature-color ramps. Their combinations allow to reach visual complexity. Usable on mobile platforms due to quite simple calculations.

Same approaches suitable for projectiles and trails as well as for muzzle flashes, flamethrowers, lightning or electricity arcs, etc.

This work still in progress. 

Follow for updates and thanks for watching.