I'm not sure how complete it is, but HN user citizenkeys keeps a nice index of YC companies listed by batch. http://ycuniverse.com/ycombinator-companies#ycw13

I'm not sure how complete it is, but HN user citizenkeys keeps a nice index of YC companies listed by batch. http://ycuniverse.com/ycombinator-companies#ycw13 http://ycuniverse.com/ycombinator-companies#ycw13