In Patch 1.03 (March 2022) for Elden Ring came a listing "Added night background music for some open field area(s)."
This included some night music that plays during night time combat in Caelid.
After not seeing it some 9 months later literally ANYWHERE on the internet, I decided to finally record it myself as it's an absolute bop. Unfortunately I can't seem to find any more 'official' information about this track, so this will have to suffice unless Bandai / FromSoft release any information about it, which is doubtful.
Assumed credit to Yuka Kitamura, who produced the 'Caelid' sountrack (though again, this is unknown whether this track is her work or not)