Here are a few that seem to pop up a bit in the blues that I noodle around with:

e7, a7, b7, g7, d7...

you get the idea.

I'm sure the gurus here can give you a far better and more in-depth answer than that.

Oh yeah, one other thing; I've found that your right hand will help you sell the blues as much as your left. Get a good grasp of a shuffle and triplet feel and it'll come together nicely for you.

Good luck.