Josh, I see Business and Tech got porn-spam blasted again. I find that IP lists, by country, are helpful. Sometimes there will be a huge block in say, Belarus or Vietnam, that is pretty much certain to be a source of spam, and you can use asterisks to block the whole range without keeping out regular members or legitimate newbies.
For example, Belarus has a huge block between addresses 37.212.0.0 and 37.215.255.255. If you ban this: 37.21*.*.* you will ban 262,000 IP addresses at once. This website:
https://lite.ip2location.com/ip-address-ranges-by-countryhas all the IP ranges, by country. I recently cut spam in half at my website by banning several IP ranges in Ukraine and Russia that comprised about 4 million IP addresses. Didn't lose a single real member. Hope this helps (and realize you may know this stuff already).