Hi Slide,
Welcome to the forum.
You can find the old ST-XX disks on the following link:
https://archive.org/details/AmigaSoundtrackerSamplePacksst-xxI haven't found a sample repository so far so best is to ask musicians directly or take sample from mods like in the old days (and give credit).

btw, if you happen to have mods for us please send to our ftp.
cheers buddy