a directory? no, i don't know of one off of the top of my head. however, https://btcmap.org/communities would help you for local places.
Discussion
Someone on Twitter mentioned OshiApp as well, also with a local/brick and mortar swerve. I love the idea of supporting local businesses, especially supporting local Bitcoin welcoming businesses. However a directory of online merchants might apply to more people at scale. Checking these to see if any of them listed here and elsewhere have bitcoin e-commerce might be a good place to start.