Either Soulseek (Which still manages to be my one-stop shop for this kind of thing) or forums, but you’d have to find an active forum related to that niche. For example there’s Squidboard for game and anime soundtracks

Always worked for me, high res and all… The issue is only with Shutterstock, alamy etc are still working fine

Saeed

Brazilian group

Russian group

Telegram is the best place for it, imo. You start from the surface in public groups and channels, then search the group messages and pay attention to where the forwarded messages and links come from. Just keep digging deeper.

A lot of good groups got nuked this year, tho. It’s not that common but still happens. They always return, just keep an eye for info in public channels.