1. Tourist Trap (1979)
2. Poltergeist II (1986)
3a.
Frankenstein (1931)
I have to revisit the Universal Monsters at least a few times each year, and there's always a good chance that one of those times will be the Frankenstein series. I know old films aren't for everyone--they weren't for me for the longest time--but I really can't recommend these enough (well, the first three, anyway). There's a good reason people are still talking about them 80 years later.
I actually think the first one is the weakest of the three, mostly just because it lacks wonderful side characters like Pretorius and Ygor to steal the show. (Dwight Frye's hunchback Fritz is fun, but is given comparatively little to do) But Karloff's performance as the pre-speech monster is still wonderful, and I love Colin Clive's manic energy a lot more than his reluctant role in the sequel. The lack of a score and long periods without dialogue really add to the atmosphere of pre-Code horror.
3b.
Sleepaway Camp (1983)
This one is most notable for its shock ending, and honestly, that's pretty much all it brings to the party. And I even have my problems with that, which I won't go into for the sake of anyone who doesn't already know it. Basically, it's a great twist that lands with a thud due to a laughably bad reveal.
If you've never heard of the movie, the title alone is probably enough to let you imagine about 80% of it and be right on the nose. A couple of the kills are okay, but none of the characters are memorably likable or unlikable. The one exception is the predatory cook pictured above, who gets it early and gruesomely.