Hardcore collectors are still discovering one-off acetates and tape recordings
from long gone 1960s / 70s publishing companies..

Many are anonymous discs with scant details handwritten or rubber stamped on the lables..

There's big money to be made on ebay if they can be linked to celebrity names
who were pre-'fame' young jobbing session players / singers to earn extra money...

There was a pool of fairly well known musicians who had a side line income
churning out genre music for film and TV media library companies..

"Right then lads, you are booked in the studio for half an hour this afternoon to record a 3 minute folk sounding track,
like that rubbish those hairy smelly students like to listen to.
Just don't make it to close to a record we can get sued for.
You can make up the words and music in the pub this lunchtime.
We're certain we can flog the track to a new pagan sex horror comedy
in production in the west country..."

... something like that...

This is the stuff us music obsessives drool over...