I'm an extreme newbie spriter (I just started a few days ago) so don't expect anything too amazing.  Anyhow:

Characters:
          
From left to right: Random bald guy.  Character based on a drawing by my friend (Can be found here).  Aqua slime: generic slime character.  Grassy little character meant to blend in with the grass.  I put him on black and grass for comparison.

Tiles:
   
From left to right: Grass, there are actually three different tiles this are displayed in that pic.  Rock/cliff wall.  Note: Both of these are 16x16 and have been tiled a bunch.

C+C is appreciated but I probably won't edit any of these sprites since they're more or less just for practice.