I love to handpaint normal maps using just photoshop without doing any highpoly at all. I only do this when the polycount is kept quite low and the texture size is as small as possible.
When I work like this 90% of the work is done with the pencil tool in one pixel size (not the brush tool). The rest 10% of the work is done using any tool that photoshop can provide. I also have the "NVidia normal map" filter, but I barely use it. I only use it when I handpaint an organic "height map" and I whant its normal map, or when the UVs contains alot of diagonals. But when I use this filter I never use the resulting image, because with the texture sizes I'm working on are very small, the resulting image that the filter produces usually is quite blurry and messy. So, whenever I use the filter, I only use the resulting image as a reference to then paint my own normal map.
The images I'm going to show you are my own projects, they are not done for any actual game or anything. I just do them because I enjoy it so much. The first images I'm going to show are basicaly simple objects, and then I will show more complex objects at the end. The shaders I use for this are very simple, they only use difuse map, normal map and specular map. The screenshots are taken directly from 3dsMax, not using any game engine.
I hope you like it!
Scorpion Evo3 :
I like guns, so I made a few. Polycounts and texture sizes are consistent with the rest of the objects.
There is something I whant to say for the last object. I did this object and the normal map back in 2011. Since then I have improved alot, so today I would have done things quite diferent. I'm not particularly pround of the underneath part of it, but at that moment I was already too bored with the object, so I kept it as it is. Also, I never did the difuse texture, so I've created a very simple one just to show you how it could look (No specular map here). Still I think is good looking enough to show you.