1fichier.com premium is really inexpensive atm (3 €/year!), so you should definitely check out that site/offer (note that "all" of my uploads have a 1fichier mirror).
If you can make a list of your missing releases, I'll see what I can do for you. (I was planning reuploading the 3DS ROM set in plain zip format anyway but have no "deadline" right now.)
Regarding usenet: It's really not complicated. You just need a usenet provider and a usenet search engine like binsearch.info (not needed if you have access to nzb files directly).