22.214.171.124 - 126.96.36.199 188.8.131.52/18
This IP seemed awfully familiar so I checked.
184.108.40.206/18 (already blocked) Limestone
220.127.116.11/18 (already blocked) FDC
18.104.22.168/19 Voxel Dot Net, including ExactSeek
that leaves only
which turns out to be Lightpoint "colo and hosting".
ExactSeek is currently classified as "no skin off my nose". But if you feel differently, that means you could happily block all of
and be done with it.