Seriously? I'm subscribed to eweka and news hosting for nntp, as well as nzbgeek and nzbfinder for my indexers. Nzbgeek has a lifetime subscription option. You can get anything you're looking for. It's a simple subscription process.
What are you considering as 'top tier' that won't take a subscription?
sorry to break your bubble, they are good but they aren't the top tier usenet indexers i am talking about.
the top tier i am talking about has a "fight club's rule 1". they take donations but simply won't give you an account if you are willing to get inside.
Usenet is easier to take down because its a centralized server and you essentially just pay for retention of files. the better Usenet providers have longer retention.