I've got brushes and sponges from A to Z but nothing compares to Sonia Kashuk's cute purple blending sponge for makeup application. I fell for the beauty blender and bought it but Sonia's brush is much more user friendly.
It's inexpensive but gives you such a great look - I use it for foundation, concealer (on days I just have to have it) and even cream blushes (which were always challenging for me).
The pic is of the blue one - which was her first design - it now comes in purple (newer one).