@Terra here are some to potentially look for on your streaming services.

http://imcdb.org/movie_968741-Comet-Impact.html - Old small grainy mains.
http://imcdb.org/movie_1747924-My-Future-Boyfriend.html - this one too seems to need replacement HD images.
http://imcdb.org/movie_1151915-Nothing-Like-the-Holidays.html - neptune said some captures are HD but a lot of grainy and do not appear HD.
http://imcdb.org/movie_4518272-I-Killed-My-BFF.html - Doesn't seem to be HD.
http://imcdb.org/movie_5161386-Imposture.html - Doesn't seem to be HD.

I placed a comment in the admin section to see if there could be a possible HD button or box checked so we can tell which images had HD upgrades. Not sure if it will get implemented but I placed the request in.

That way if any of the above films were in fact HD upgrades then I would have seen the 'button or box' and would not have included them on this list.

Edit: Removed movies that you completed in HD