This can't be said enough.
Large numbers of users still have no idea that their blocker works at all because of these lists.
The collective amount of work which goes into these free-to-use lists on a daily basis is impressive, especially considering it's done entirely on a voluntary basis.
To get an idea just glance at the commit rate:
EasyList/EasyPrivacy: https://github.com/easylist/easylist/commits/master
uBlock Origin: https://github.com/uBlockOrigin/uAssets/commits/master
Add to this all the regional lists, specific-purpose lists, the hosts files (Peter Lowe's, Dan Pollock, malware lists), etc.