Can't really say much for manga, as I just get it all from here (and consequentially, I don't really have anything that isn't here, or was here at one point.)
For anime though, I just started writing down all of the groups I got stuff from. I went through everything I currently had, and ended up with 90 different groups or individuals who'd done at least one thing I'm holding onto. From there, it's mostly just following bakabt torrent links or looking them up on anidb (worst case, googling them outright, since I already have the name.)
Not all of the groups I've got listed still exist, but quite a few still do, and even some of the dead ones still yield worthwhile content. Bookmarking the groups and just separating them into inactive/active worked for me.