It's been decades since I've seen it but I really remember loving Woody Allen's Stardust Memories released from that year, but I need to watch it again. The same goes for The Elephant Man, though I remember that film far more. Loved both of them, but they are due for re-watches before I'd rank them, but both would certainly be at the top of my list of 1980 (the year, not decade) films. I also remember liking The Last Metro by Truffaut a lot too, but it's been years since I've seen it.
Raging Bull of course is great and would be toward the top. I also liked two films that are reasonably well known, but not necessarily considered true classics: Heaven's Gate and The Long Riders.
The Long Good Friday is really a cool British gangster film and of course The Shining by Kubrick is a bonified and well recognized classic that is amazing.
Funny thing, last October we saw The Shining in the theater and I had a discussion afterward because I swear that thing is a low-key subtle comedy. It's absolutely catch you off guard hilarious and I had always slightly been aware of something there to the humor, but until I watched it in the theater, it didn't stand out to as prominently as when seeing it on the big screen. For instance Jack reading Playboy in the waiting room (just as our "heroes" in Dr. Strangelove did) and also the huge HUGE setup of Scatman Crothers coming to "save the day!" and then how anticlimactic, sudden, and shocking his death was. His murder seemed more like a satire of how horror movies tend to go and really just seemed like a dig against horror movie conventions. I also love Jack's response to Duvall while driving up to the Overlook Hotel, "See, he saw it on television; it's OK!" I think Duvall played her role straight, but I swear Kubrick and Nicholson had an agreement to do The Shining as a three layered film... horror on the surface, horror on the inner layer underneath, and dark comedy at the core.
Airplane! is great from that year too and Kurosawa's Kagemusha is a film I was bewildered by and need to watch again too.
Yeah lots of interesting films from the year the ushered in the 1980s.
My favorite is The Empire Strikes Back, which I recently wrote a review of sorts in my top 100 films of all time thread linked at the bottom of my posts in the bio-section or whatever it's called.
Also MUBI does a cool top lists of by year if you're looking for some ideas or want to "blind watch something." I'm really interested in The King and the Mockingbird:
https://mubi.com/en/lists/mubi-s-top-50-films-of-1980