An explosion test I made in Blender, retouched in paint.net (added background, edited shape). The domain had a base resolution of 50 divisions, and high resolution with 2 divisions. The smoke flow object was particle-based, with 250 particles.
This is some more smoke I made in Blender with a physics simulation and a volumetric shader, this time colored blue:
This is an image of some smoke I made in Blender with the built-in smoke simulator and a simple volumetric shader.
This is some rainbow smoke I made in Blender using the built-in smoke simulator. I have six different meshes emitting different colors of smoke in the same domain.