Looking at my library I don't have many remakes in it at all relatively speaking; I have more remasters but those don't really count here.
People tell me the Final Fantasy VII Remake is great but I just can't get on board with the way they split the game up and are now just getting around to adding even more content to part 1 (Yuffie) on PS5 that wasn't there on part 1 of the PS4 version. I hate the way they went about this so I haven't bought it and am just gonna wait until they finish it up.
The modern Resident Evil 2 remake is pretty great and I have that one, but that is already popular so I'll put a word in for some more obscure ones.
The Trials of Mana remake on modern platforms is even better overall than the Super NES original thanks to gameplay changes and content addition.
Duck Tales: Remastered is not really a remastering of the NES game but a full remake of the old game that I enjoyed a lot (plus the production value of the voice cast from the 1980s cartoon) even if the new level at the end made me yell a bit at its difficulty.
Lunar: Silver Star Story Complete and Lunar: Eternal Blue Complete on the PlayStation are both great remakes of the Sega CD role-playing games. If I have a complaint for each it’s that L:SSSC loses much of the great music of the Sega CD game for new compositions and L:EBC loses some interesting story scenarios that existed in the original, though both also add much in their favor.
The Dragon Quest series and Final Fantasy series remakes - if you can call them that - for PSP (Final Fantasy I & II and Final Fantasy IV Complete Collection) and DS (Dragon Quest IV, V, and VI) and 3DS (Dragon Quest VII) are great.
I didn’t like the new 3D art and difficulty changes to the complete 3D remakes of Final Fantasy III and IV on DS and PC though even if the new story additions are fine and round out their stories more. The mobile/PC ports of the good (except for the music quality and resolution) Game Boy Advance remakes of Final Fantasy IV, V, and VI unfortunately don’t look so hot because the assets are all at different mastering resolutions thrown together which makes them graphically look inconsistent.
Ditto for Super Mario All-Stars on the Super NES being good. There’s some minor changes in the physics of the originals but I don’t really care.
Metroid: Zero Mission on Game Boy Advance is a great reimagining of the original title that started it all.
There's unofficial fan remakes on the PC that are excellent like AM2R (Metroid 2 remake) and the Streets of Rage Remake (Streets of Rage series remade into one game), both of which were so great that Nintendo and Sega shut the original developers down as they didn't want to have to compete with them.