We just released five free, responsive email templates over at Litmus. We're referring to them as Slate, and they represent five emails that pretty much any business should be sending their customers. 

Based off of the Salted template, they are nice and responsive and thoroughly tested. You can read a bit more about them on my blog.

Ted Goas has built up an excellent set of patterns in the Cerberus template. Check it out ≫

If Sass is your jam, Alex Ilhan built out the responsive email framework just for you. Check it out ≫

The original Salted template that accompanied my A List Apart article on responsive email. Check it out ≫

Not really a template, but an amazing collection of design patterns (with code) for responsive emails. Check it out ≫