I recently was looking for them but it seems UG was the only source. I can't remember who did it but the user basically did remasterings (no arrangements) of chosen NES games where there is no OST in the first place or only of mediocre quality. For example he remastered the Rockman series (labeled as #0004L) and I think he also treated DuckTales besides other games. The files were provided as 48khz, 16bit flacs. I was hoping that maybe the user is present here or that some other ex-UG-member managed to get these before the shutdown of the tracker (any news about a successor?) and could upload them.
I can offer the Rockman remasterings as mp3s. Here is an example of Dr. Wily Stage 1 from Rockman 2:

MP3:
UG-remastered_example.7z - anonfiles (https://anonfiles.com/file/8c0c379143fb142917762574a07017c8)

Password:
ffshrine.org