Disconnect Pro for iOS is also a great tool. Hasn't failed me yet and makes adding custom trackers super easy via the list of recent connections. I blocked 30.8k trackers and saved 3 GB of data last month. :)
Yes. I use a DNSBL in my router (pfBlockerNG), and I've been considering writing a small script to resolve every IP in the blocklist and then block outgoing connections to those IPs.
Of course this is only useful at home. As soon as my phone leaves the house, everything is open again.
Ooh, good idea. Would probably only have to write ~1 time per day to a separate, parallel list. Or have a small VPS do the work continuously and push changes to a Git repo so others can pull it however often they want.