David Kalat is responsible for many of the best, most interesting audio commentaries released on boutique label film releases. They're so good, they always warrant a purchase from me even if I'm not sure I'll be into the film itself. Here's a comprehensive list of films where Kommentaries are available. I saw other lists, but there were gaps. This is all of them, I think, with a few notes for when it isn't obvious where the commentary can be found. Let me know if I'm missing any!