Newly Registered Domain block lists for PiHole[0]. This has worked hands-off for the last two days after a couple of weeks of tweaking. My PiHole blocklist is currently a bit over 14 million domains, of which around 8 million are NRDs.
My next item is to add AbuseIPDB IP addresses to my "Uninvited Activity"[1] IP address blocking system, implementing xRuffKez's script here: https://github.com/xRuffKez/AbuseIPDB-to-Blackhole
Unfortunately, but also understandably, AbuseIPDB limit their free-access (account required) API to 10,000 IP address records. So I might be putting it into a database to hopefully aggregate multiples of the 10k results if they're not always the same 10k.