I take no credit for these and have no idea why Nyx hasn't uploaded these themselves, and if they ask me to take them down, I will. Until then, here are some of their mixes.

Deltarune Chapter 2 - Epic Rouxls Battle [Epic Symphonic Metal Remix By NyxTheShield]

NEED TO KNOW (MAKS SCHRANZ EDIT)

JINAC

ice cave 2 146 bpm august 14 take 1

This theme is so awesome and ominous. Really spooks out a good haunting theme.
Download Link: http://convert2mp3.net/en/index.php?p=complete&id=youtube_9IEnIdCBYSc&key=6VfZ3CN0QY1T

Paper Mario the Thousand Year Door - Shadow Queen Battle theme(Remix)

Here's a traditional Japanese remix of Necrozma's battle theme!

Pokemon Ultra Sun and Moon: Necrozma Theme ~ [Traditional Japanese Remix]

Kalbur - Megalovania (Original)

Original song : https://www.youtube.com/watch?v=xL8nfwF0LRc

Final Battle Vs. Primal Giratina (UNOFFICIAL) - by Hnturs12 and LD3005 (original in the description)

Artist: モリモリあつし
https://www.youtube.com/user/GilvaSunner

“Masked, I advance.” ― DeDeDescartes

Hello everyone! There's my new remix from game Hollow Knight, here you have Orchestral Epic Cover from Broken Vessel and False Knight in one song! I hope you enjoy :)

Final Battle Vs. Primal Giratina (UNOFFICIAL) - by Hnturs12 and LD3005 (original in the description)

Enzoul