Gaur Plains 8-BIt:
https://www.youtube.com/watch?v=xkrf4xfDsZs
Xenoblade Chronicles Remix Compilation:
https://www.youtube.com/watch?v=Ryi1bxVMmzU
(It's one of the first Remixes on could find before the Smash reveal)
Xenoblade Chronicles OST Live by ACE (Remaster version):
https://www.youtube.com/watch?v=h0dW8Gk8VvE
Not a Remix, but that's not a reason to not include it.
Hellion Sounds - Mechanical Rhythm /Xenoblade (image has massive spoiler in it)
https://www.youtube.com/watch?v=3UrMqbXNzCk
Reminds me of Guilty Gear for some reason
Final Boss {Xenoblade Chronicles}| 8-Bit Remix (VRC6)| Famitracker
https://www.youtube.com/watch?v=Ma-nf_uaf-4
Its a massive spoiler for everyone who hasn't played it yet so I don't know
Xenoblade Chronicles - 8-bit One Who Gets In Our Way on Famitracker
https://www.youtube.com/watch?v=RvWoFBC0RDo
I like it more than the Gaur Plains 8-Bit Version
Xenoblade Chronicles - Unfinished Battle / 引けない戦い (Cover)
https://www.youtube.com/watch?v=ug0y5GGGkRI
Again technically not a remix but this cover was too good to not include.