[asnrk]

The most useful ones are already free. So, probably none that I don't already. Development resources (free, hosted by companies with incentive to spread the info). Wikipedia. Rarely I still manage to stumble on some non-monetized hobbyist sites, despite their being hard to find under current search algos (infrequent updates, no attention to SEO, no padding things to look like "more unique content per page" to Google), and that's nice.

The rest I already pay for (Netflix, which just barely skates by being so cheap), are essentially utility things (bank sites, government), or are so low-value I'd probably be better off not using them, frankly. Or are simply piracy sites (library genesis / scihub), for that matter.

Any topic I scratch the surface of in online research I end up at excellent, totally free (not ad supported) resources or finding that I need to track down some books, or some combination of the two.