We have done this list to help those who struggle with or have struggled with compulsive gaming or video game addiction. It can also help parents limit their children's online play time.
Just add the following list to your pi-hole.
https://raw.githubusercontent.com/jhidalgo3/pihole-blocklist/master/game.txt
https://dbl.oisd.nl/
https://raw.githubusercontent.com/outapzaza/blocklist/master/list.txt
https://raw.githubusercontent.com/outapzaza/blocklist/master/fingerprintblock.txt
https://raw.githubusercontent.com/outapzaza/blocklist/master/serverblocklist.txt
https://raw.githubusercontent.com/outapzaza/blocklist/master/regex.txt
https://raw.githubusercontent.com/blocklistproject/Lists/master/ads.txt
https://raw.githubusercontent.com/blocklistproject/Lists/master/malware.txt
https://raw.githubusercontent.com/mkb2091/blockconvert/master/output/domains.txt
If you don't have a Raspberry PI, you can edit your hosts file with these settings.