74.63.128.0 - 74.63.191.255 74.63.128.0/18
This IP seemed awfully familiar so I checked.
74.63.192.0/18 (already blocked) Limestone
74.63.64.0/18 (already blocked) FDC
74.63.32.0/19 Voxel Dot Net, including ExactSeek
that leaves only
74.63.0.0/19
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
74.63
and be done with it.