I've been looking into it as well. Vimm has the largest library of games available for easy downloads, but there are sites like 'RomsGet . io' that have the same games to try if downloads are still being spotty for you.
Any particular games you're looking for? All three of these websites had every game I personally own, so I'm not sure if you are hunting down the obscure games. So far, they seem to be pretty complete. Looks like I got some downloading to do so I can get my collection set up on the family funstation.
Edit: the previous sites I mentioned just gave me parts of files instead of all the parts needed to make a full 7zip, so I removed the links.
The Weebs fleeced my vidja collection.