Attempted old sign on Union St. NW at Pleasant St./Columbian St. in South Weymouth. It may or may not actually be old, but it's still an attempted sign.
Washington St. (a state-maintained road) at High St. in Dedham, a relic of when signals were first installed.
Adams St. WB in Quincy at Newport Ave., also the extension of Burgin Parkway. Because it's unclear where Burgin Pkwy. ends and Newport Ave. begins, I think this is still a state-maintained highway at this point - a logical changeover point would be the north side of Adams National Historical Park at Furnace Brook Parkway.
Speaking of the Furnace Brook, here's a new sign in an old (1960's) style looking east on Copeland St., and a stone-textured railroad bridge on Furnace Brook Parkway NB with a faded clearance sign. This is an official MDC parkway, whereas Burgin Parkway is not (and may or may not even be state-maintained, though I would bet it is because it connects a major freeway (MA 3) and a T station).
East St. heading north from Cedar St. in Dedham.
Village St. WB, obviously in Midway.
On the north side of Hartford Ave., and I don't have to tell you where.