I've messed around a bit with the army painter trying to get some chaos chapters. So far I've got Thousand Sons, Sons of Horus, and Emperor's Children. Pretty happy with the first two, third one needs work. If anyone has anything good I'd love to see it.

Thousand Sons - Kantor Blue, Blood Raven Red, Auric Armour, Nuln Oil Black.
Sons of Horus - Castellan Green, Silver, Light Earth, Nuln Oil Black.
Emperor's Children - Xereus Purple, White Scar, Balthasar Gold, Abaddon Black.

These are pretty much all metallic variants.