This was a stylized solution I developed for Warden: Melody of the Undergrowth which allowed us to have dynamic flickering fire.
The cartoony fire was created through the use of carefully constructed 3D mesh, inverted cloth physics and layered elements. Combined with bloom and an additive shader it creates a lovely stylized effect.
Optimization could happen by moving away from cloth physics to a noise texture for moving the vertices however this is much less dynamic and we required a solution that allowed the players torch to react to their movements.
Originally we experimented with traditional particle systems but found they rarely reached the art style we aimed for and thus we required a smarter solution.