Well, let's get the unlikely ones out of the way first...
Silent Hill 1 Remake - Fans have been clamoring for a remake of the first Silent Hill for a good ten years now. The original is still amazing and holds up today in terms of atmosphere, music, story and (surprisingly) gameplay. The one thing that has always held it back is its graphics. Compared to SH2 which features beautiful graphics and visuals that still look pretty good today, SH1 looks extremely dated. The thought of experiencing this game's incredible story with modern graphics, seeing characters like Harry Mason and Alessa in ray tracing enivironments.... is just breathtaking.
At first I was against a remake because I think it would create big problems with the lore which is perfectly synced between SH1-SH4. Then I realized that we already have lore-breaking games such as Origins and Homecoming that **** up the universe completely, plus you could always do like developers always do and proclaim that the remake is not a remake but a "reimagining" that takes place in an alternate timeline. Unfortunately a remake will never never never happen because Konami owns the IP, and they don't know **** about how to treat their properties. Especially Silent Hill.
SSX Tricky Remake - If there's any game that would be extremely fun to experience with modern graphics, it's definitely SSX Tricky from 2001. The game just screams the early 00's and features so many colorful and unique characters. The tracks are insane and over the top, and I think a remake should make them even bigger and have more shortcuts. If possible, I'd also love to see new tracks added to the already exisiting ones. Unfortunately, the IP is owned by EA so a remake will never never never happen. However, Steve Rechtschaffner who was the producer for the game said last year that he's currently working on a spiritual successor to SSX called "Project Gravity". Although I'd rather see an actual new SSX game with him behind the wheels, that might be the closest thing we'll ever get to a remake. As cool as it is to know that Rechtschaffner is working on a new snowboarding game, it's going to be free-to-play which is never a good sign these days. It will also be a low budget game, that's for sure.
Other than those very specific two, I'd also like to see remakes of the following games (that are more likely to happen, too):
Code Veronica
Dino Crisis
Red Dead Redemption 1
Populous