DNSBL
DNS Block Lists provide you an easy way to block unwanted network traffic. This is useful for blocking ads, adult content, tracking, and malware. There are a lot of lists out there and some will require you to triage and whitelist blocks of legitimate traffic. The great thing with pfBlockerNG (not sure about pihole) is that any duplicates are automatically removed.
Current Lists
Below are the lists I currently have deployed using pfBlockerNG on pfSense.
Pihole DNSBL
https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts
https://mirror1.malwaredomains.com/files/justdomains
http://sysctl.org/cameleon/hosts
https://zeustracker.abuse.ch/blocklist.php?download=domainblocklist
https://s3.amazonaws.com/lists.disconnect.me/simple_ad.txt
https://hosts-file.net/ad_servers.txt
Adult DNSBL
https://raw.githubusercontent.com/StevenBlack/hosts/master/alternates/porn/hosts
https://raw.githubusercontent.com/chadmayfield/pihole-blocklists/master/lists/pi_blocklist_porn_top1m.list
Malicious DNSBL
https://raw.githubusercontent.com/ZeroDot1/CoinBlockerLists/master/hosts
https://v.firebog.net/hosts/Airelle-hrsk.txt
https://s3.amazonaws.com/lists.disconnect.me/simple_malvertising.txt
https://hosts-file.net/exp.txt
https://hosts-file.net/emd.txt
https://hosts-file.net/psh.txt
https://mirror.cedia.org.ec/malwaredomains/immortal_domains.txt
https://www.malwaredomainlist.com/hostslist/hosts.txt
https://bitbucket.org/ethanr/dns-blacklists/raw/8575c9f96e5b4a1308f2f12394abd86d0927a4a0/bad_lists/Mandiant_APT1_Report_Appendix_D.txt
https://v.firebog.net/hosts/Prigent-Malware.txt
https://v.firebog.net/hosts/Prigent-Phishing.txt
https://raw.githubusercontent.com/quidsup/notrack/master/malicious-sites.txt
https://ransomwaretracker.abuse.ch/downloads/RW_DOMBL.txt
https://v.firebog.net/hosts/Shalla-mal.txt
https://isc.sans.edu/feeds/suspiciousdomains_Low.txt
https://isc.sans.edu/feeds/suspiciousdomains_Medium.txt
https://isc.sans.edu/feeds/suspiciousdomains_High.txt
Ads DNSBL
https://adaway.org/hosts.txt
https://raw.githubusercontent.com/StevenBlack/hosts/master/data/UncheckyAds/hosts
https://filters.adtidy.org/extension/chromium/filters/15.txt
https://v.firebog.net/hosts/AdguardDNS.txt
http://s3.amazonaws.com/lists.disconnect.me/simple_ad.txt
Suspicious DNSBL
https://hosts-file.net/grm.txt
https://reddestdream.github.io/Projects/MinimalHosts/etc/MinimalHostsBlocker/minimalhosts
https://raw.githubusercontent.com/StevenBlack/hosts/master/data/KADhosts/hosts
https://raw.githubusercontent.com/StevenBlack/hosts/master/data/add.Spam/hosts
https://v.firebog.net/hosts/static/w3kbl.txt
https://v.firebog.net/hosts/BillStearns.txt
https://www.dshield.org/feeds/suspiciousdomains_Low.txt
https://raw.githubusercontent.com/piwik/referrer-spam-blacklist/master/spammers.txt
https://hostsfile.org/Downloads/hosts.txt
https://raw.githubusercontent.com/Dawsey21/Lists/master/main-blacklist.txt
https://raw.githubusercontent.com/vokins/yhosts/master/hosts
Tracking / Telemetry / Fake-news DNSBL
https://v.firebog.net/hosts/Airelle-trc.txt
https://v.firebog.net/hosts/Prigent-Ads.txt
https://raw.githubusercontent.com/quidsup/notrack/master/trackers.txt
https://raw.githubusercontent.com/StevenBlack/hosts/master/data/add.2o7Net/hosts
https://raw.githubusercontent.com/StevenBlack/hosts/master/data/tyzbit/hosts
https://gist.githubusercontent.com/CHEF-KOCH/080efada22b9659ef61241029122873b/raw/7f9bd984d3c46b3dba2de7606da579bc0ac6780c/Canvas%2520Font%2520Fingerprinting%2520pages%2520%255B2017%2520Edition%255D
https://gist.githubusercontent.com/CHEF-KOCH/5a7b1593d1880f906b12a3c87cee4500/raw/3ba028508feb2ef67a3d7ab75f428fd284223e8b/WebRTC%2520tracking%2520list%2520%255B2017%2520Edition%255D.txt
https://gist.githubusercontent.com/CHEF-KOCH/63fd2e506cb34a2378ad2620ab06d2e0/raw/fb9f16e3ac998d3f773ebdfee4aa3bfd10a5d763/Audio%2520fingerprint%2520pages%2520%255B2017%2520Edition.exe
https://gist.githubusercontent.com/CHEF-KOCH/2dea75d43b2184f228ae94b168d275b1/raw/35d7a4447a198449bbb3280e1c3d7a57517350de/Canvas%2520fingerprinting%2520pages%2520%255B2017%2520Edition%255D.exe
https://v.firebog.net/hosts/static/SamsungSmart.txt
https://v.firebog.net/hosts/Easyprivacy.txt
https://raw.githubusercontent.com/TakoYachty/Gift-Card-Killer/master/giftcardkiller.txt
https://raw.githubusercontent.com/WindowsLies/BlockWindows/master/hosts
http://s3.amazonaws.com/lists.disconnect.me/simple_tracking.txt
https://raw.githubusercontent.com/StevenBlack/hosts/master/alternates/fakenews-gambling-porn/hosts
Please comment below with your own DNSBLs, feedback, or suggestions.