To emit light, you don’t have many other choices - either a PointLight or raytracing (these options are able to create actual light sources within the scene, not only casting shadows.) Material.emissive, shaders, and postprocessing can’t really do that - since they work either on single objects, or entire rendered scenes, at least in the default WebGLRenderer.)
If there’s some specific style - a video / screenshot of what you have in mind - it might be a bit easier to help.