In a perfect world, you should receive all the nodelists you need via the fileechos of each network. In my reality, this often doesn't work for various reasons...
So, I've started fetching my nodelist updates from all over the internet using curl, ftp and many regular expressions.
This way, I've managed to find reliable update sources for a few of my networks and I'm constantly working on finding more.
Here, you can easily download the latest nodelists and nodediffs for these networks:
Please feel free to use direct links for your automation.