Okay, so I love the 224 for blending. Absolute necessity! And then there's the 219, which is the pencil type brush. If you have a tiny crease (as do I), this is essential for putting color in your crease. For just applying color, I have a Japonesque brush that's sorta like the 213, or I'll use a 272, which is an angled goat hair brush. The 272 deposits more color, while the Japonesque one is better for sheering things out.
So, basically, the must-haves are the 224, the 219, and either a 213 or a 272.