Very nice pieces, I think the most aesthetic one is probably the zebra, I like your use of color and composition.
The graphite one has some conflicting angles and is a little dark in contrast, but that may be the camera.
The next one up (blue jumping horse) is a Little difficult for me to tell, it looks to have nice contrast, maybe some more mid values would even it out. I like the canvas painting of the mare and foal, very cute. I would have to say for that one try to pay attention to you subject placement as it is a bit odd, even if it was from a picture or not, try keeping a rule of thirds in mind to keep the piece interesting, though I like the color and tones in this one.
And the style is very attractive in the wolf one, I would like to maybe se a bit more detail personally but at the same time the blurryness it interesting and well done.
Nice work :)