One that that always comes to mind for us is Gears of War: Ultimate Edition. When it released back in 2015 we actually thought Xbox 360's Gears of War still looked good and played pretty well - but our entire perspective changed after playing through the remake's campaign and multiplayer modes. Some may argue that this was more of a remaster, but Gears Ultimate was entirely rebuilt for Xbox One - adding in some extra PC-exclusive campaign levels to boot. This one is definitely on the edge of that remake/remaster debate, but we look at it as a brilliant remake considering the glow-up it delivered for Gears fans last generation.
One remake that can't be argued against in the slightest is Resident Evil 2. Yes, we're talking about another Capcom RE remake here but RE2 was masterful - and it was so different to the original PS1 release in many ways. Despite playing so differently, this 2019 re-imagining still captured the essence of what the original delivered all those years ago - and its new version is one of the finest examples of how to bring a classic into the modern era.
There's lots of other releases you could make a case for being the best Xbox remake as well, including Halo: Combat Evolved Anniversary, Call of Duty: Modern Warfare Remastered, Crash Bandicoot N.Sane Trilogy, Spyro Reignited Trilogy, Destroy All Humans! The list goes on...