Really liking the characters you come up with!

Critique: The highlight on his nose is too similar to his mouth, and I feel the shading could be a bit more defined (more highlights/shaded areas) on this one.

Good work. Keep them coming please! :)

One note on the shading.  It looks like the light source is directly above, except for the beard, which looks like it's from the left.  I would consider having the beard shadow wrap around the bottom of the beard for consistency in the direction of your light source.  Also, maybe shade the lizard a bit too.

Very good all in all, though :)