List of possible image features for content based image retrieval
The field itself is too vast. So i doubt you can have a fully exhaustive list here. 
However, MPEG 7 is one of the primary effort in standardizing this area. So what is included here is not universal - but at least the most primary. 

Here are some key feature set which are identified in MPEG7 ( I can really talk only about Visual Descriptors not others see this for full scope). 

There are 4 catagory of Visual Descriptors:

1. Color Descriptors which includes :
Dominant color,
Color Layout (essentially Primary color on block-by-block basis)
Scalable Color (essentially Color histogram),
Color Structure (essentially local Color histogram),
and Color spaces to make things interoperable.  

2. Texture Descriptors (see also this) which includes :
Texture Browsing Descriptor - which defines granularity/coarseness, regularity,and direction. 
Homogeneous Texture Descriptor - which is based on Gabor filter bank. 
and
Edge Histogram 

3. Shape Descriptors which includes :
Region based descriptors are scalar attributes of shape under consideration - such as area, ecentricities etc.
Contour based which captures actual characteristic shape features and
3D descriptors

4. Motion Descriptors for Video
Camera Motion (3-D camera motion parameters)
Motion Trajectory (of objects in the scene) [e.g. extracted by tracking algorithms]
Parametric Motion  (e.g. motion vectors, which allows description of motion of scene. But it can be more complex models on various objects).
Activity which is more of a semantic descriptor. 



MPEG 7 doesn't define "How these are extracted" - it only defines what they mean and how to represent/store them. So research does exists on how to extract and use them. 

Here is another good paper that gives insight in this subject. 

But yes, many of these features are rather basic and may be more research will create more sophisticated (and complex) feature set.