This is difficult, because there's plenty of films that are overlooked, but whether it's a surprise that they're overlooked is another matter. I mean, I saw 'A Quiet Passion' this year and haven't seen anyone talking about it, but I wouldn't expect them to here. But, I guess I can nominate:
Margin Call
Nominating this because while it has some big star talent attached to it (Kevin Spacey, Zachary Quinto, Paul Bettany, etc.), I never se e it be discussed in the same circles as, say, Wolf of Wall Street or even The Big Short, which, in the latter case, I think this film surpasses. Very good financial drama (is that a genre?) that didn't make the same waves as its contemporaries.
Total Recall
No, not the Arnie one, the 2012 one. And maybe it's not fair to say it was overlooked, as in, people turned their noses up at it. Looking at its earnings, it did make a profit, but not so much that I'm surprised by the lack of a sequel. Which is a shame, because while I think the 1990 film is slightly better, honestly, I think this film is pretty good. A good action flick that easily stands on its own (mostly).
Oblivion
Now this, I'd call overlooked without question. Both this and Edge of Tomorrow are sci-fi films that star Tom Cruise. Oblivion released in 2013, EoT in 2014. Yet while I saw people talking about EoT everywhere, Oblivion seemingly came and went without a word. And...I don't get it. I think this film is pretty good. Great visuals, good action, nice bits of intelligence within its story. All in all, I really liked this movie, yet to many, it might as well have not existed. I've never seen EoT, but it just struck me as a weird roll of the dice that one Tom Cruise sci-fi action film became so beloved, while another...wasn't.
The Reluctant Fundamentalist
Why don't people talk about this?
No, seriously, why? I mean, okay, like Oblivion this got average reviews, but it's one of the few 2013 films that gets a stamp of "excellent" from me (yes, I'm pouring through my movie list folder, thanks for asking), but I've never seen this film be discussed in the context of counter-terrorism and the post-9/11 world sphere. Because, IMO, it's easily one of the best takes on the subject I've seen, commenting on the nature of terrorism, response to terrorism, cultural conflict, and the nature of fundamentalism (not just religious) as a whole. But, it seems that this is just me.
Ender's Game
I'm not going to spend too much time on this one, because I can actually understand why this was overlooked. It's a story adaptation of a YA novel in a time where YA fatigue was starting to creep up, said novel being written by an author with...certain views on the LGBT community, with fans of said novel being put off by the film due to its deviations from the novel. So, on one hand, I understand why this made a plop in the ocean. But, I quite like this film. I wish it had more of an impact, but that's the way the cookie crumbles.
Woman in Gold
There's certain films I'm not including on this list, because while they never entered pop culture, they were still well received in their own circles. For instance, Calvary, which alongside Prince of Egypt, is what I'll show to anyone who says you can't make a good faith-based film. Woman in Gold gets here only because of its lead, Ryan Reynolds.
I say this because it's no secret that I dislike Deadpool, but people were hailing it as the rejuvination of Reynolds's career. Looking at his filmography page, I can sort of see why, and indeed, this film got mixed reviews. But, I really liked it. I also think it's a demonstration that Reynolds can indeed take on roles outside cocky test pilots or psychopaths weilding katanas. But, Deadpool came out the following year, so even if this film did better critically, it would have been overlooked regardless. But, I feel this film and its lead both deserve credit.
Mr. Holmes
I'm iffy about including this film, because it gets a stamp of average from me. On the other, I think it's kind of a shame that no-one talks about it, because it's easily one of the most unique takes I've seen on the Sherlock Holmes mythos, and Ian McKellan is spectacular in the role.
2010: The Year We Make Contact
I like 2010 more than 2001.
There. I said it. I like 2010 more than 2001, whereas book-wise, 2001>2010. But, that's just me. 2010 has always been overshadowed by 2001, while the few people who do discuss it at least admit that it's a decent film on its own, even if they prefer 2001. This could easily fill an entire thread by itself, so moving on...
Concussion & Focus
I'm bringing these two up, because in the leadup to Suicide Squad, there was talk about Will Smith's career failing, or whatnot. To which I went, "huh?" Didn't anyone see these films? Well, guess not. Like I said, I'm not going to talk about every film that has gone undiscussed, but I do want to bring these up. That said, while they both get stamps of "good," they aren't without fault. Focus is primarily interesting because of its use of a two-act structure rather than a traditional three-act one, whereas Concussion has the same fault that Loving has, that the achievements in it happen regardless of the protagonist. But, especially with Concussion, I want to give Will credit. Yes, he's known for more outgoing, wacky roles, but these films can show he can take on quieter, more intimate ones.
Also helps that the films are good, if flawed.
Hunt for the Wilderpeople
This film is hilarious. Absolutely hilarious. More hilarious if you're a Kiwi, but hilarious even to those of us across the pond. Or, to me at least. But I've never seen anyone discuss it, and even Stuckmann, IIRC, brought it up specifically to give it more limelight. Heck, it's the film that gives me some hope for Thor: Ragnarok not being bland tripe as they share the same director.
Money Monster
This film wasn't really overlooked - it was discussed, and the critical consensus was "meh." As such, under normal circumstances, I wouldn't include it. However, what struck me was what was being discussed specifically, namely the idea that the film was trying to comment on Wall Street, and failing. However, I never saw it as trying to do that. It deals with these things, but it's more a commentary on social media and public perception of events rather than any inditement on the shady dealings of the financial world. So, I do bring it up here, because at least in my mind, people were looking at it wrong. But, that's just me - I'm not necessarily the "one sane man."
Anyway, I'm sure there's others, but it's a long list, and I'm iffy as to what counts as "overlooked," so, um, yeah.