Here is something i worked on for Olive, a small game we made in the AIS mod team. The characters here are mini-bosses that the player must defeat in order to progress. Each was modeled and textured by Aaron Hain, while I worked on the shaders. For comparison, we have the original models by Aaron on the left, and the models with enhanced shaders on the right.
Plant MiniBoss Shader - Features fake ambient light contribution and a Fresnel Rim light. The ambient contribution could be roughly described as the diffuse texture, to the power of the ambient light amount, lerped back into the diffuse texture. It seemed to bring out quite a few nice details in the model.
Fire MiniBoss Shader - Features fake ambient light contribution, Fresnel Rim light, and pulsating glowy bits. The ambient contribution works the same way as the Plant MiniBoss Shader, with the addition of a emissive map in the alpha channel of diffuse. An additional texture scrolls across the emissive map, causing sections to glow brightly and then cool in sequence.
Water MiniBoss Shader - Features fake ambient light contribution, Fresnel Rim light, and interpolated Specularity and FLOWMAPS! Its probably a BIT more expensive than it needs to be but it was so cool i had to do it.