I just use Terminators and Green stuff:
Ignore the Nightlords, this is just the picture I had available on my blog
The Chaos Terminator set comes with plenty of weapons to add on and you can get 5 Oblits if you like, or just 3 and 2 Lords or something.
Green stuff is easy to apply as strips of muscle n the joints.
But the Easy-to-Build Aggressors are cheaper and you could use the same technique with Green Stuff to make them look Chaotically mutated
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