I'm looking for a glow effect for a sim that I can turn on and off for storytelling. I'd prefer green if I can get it but at this point I'll take anything.

This might not be what you are looking for, but there are mods that make fairy wings invisible. (And, apparently, the Effects tool by velocitygrass http://www.modthesims.info/download.php?t=446536can be used for the same thing, because one of the mods to hide fairy wings mentioned it was made with the tool.)

A fairy with invisible wings and a little bit of skill in fairy magic can produce a green aura, with the only real drawback being that other sims in the area will get a small green light flying around them.

I haven't looked, but it's also possible that fairy auras are an effect that can be activated in a fog emitter. If that's the case, you can put the fog emitter where your sim is standing and have it generate the green glow. (I think it's the aura of Creativity that's green....)


Edit: There are several possibilities. ep7fairyauraorb, ep7fairyauraorb1_main, ep7fairyauraorb2_main, ep7fairyauraorb3_main,
ep7fairydustglow_main (that one would be white if it's what I'm thinking of) along with some other less likely possibilities.

The Fog Emitter idea is very good.
If you don't want to go completely blind, SimEve made a blog post where you'll find links to preview videos for some effects (quite a lot) and also a complete list of fog emitter's codes (here).

Alternatively, you could use Nraas MasterController (+ Cheats module) to add moodlets that give a glowy effects, I don't know them all, but there are also Bathed in Sunlight or Flight of Felicity (yellow glow) or Not So Healthy Glow (green).
Click on a Sim > Nraas > MC > Intermediate > Moodlets > Add moodlets

There is also Nraas DebugEnabler that can help add those moodlets-based effects.
Click on a Sim > Nraas > DebugEnabler > Transformation Buffs or Sim > Nraas > DebugEnabler > Add Buffs

For both, to remove the effect, just remove the moodlet (through MasterController or if you have testingcheatsenabled on, with a simple CTRL+Click).

And still with DebugEnabler, you have the option of adding a Ghost shader to any sim (without killing them): Click on a Sim > Nraas > DebugEnabler > Death > Apply Ghost Shader
When you want to get rid of the shader: Sim > Nraas > DebugEnabler > Death > Apply Ghost Shader > Deghostify

This is perfect and it uses what I already have in game, AND it should enable me to change the glow colour if I want to for storytelling. Thankyou so much!