What are some good classic frames for commuting? Specifically interested in being able to fit larger tires (~30mm, hopefully more) with fenders because that's just what I need to do here in rain+pothole country (Seattle). There are lots of 70s and 80s frames for sale but not sure what to look for that would be a good fit for commuting needs.

The Trek 520 with cantilever brakes seem great. Just hard to find in my size. Any more like this?

Thanks!