My take on a Alpha Legion descendant warband.

1. Prime with Chaos Black

Black (Armour Trim)

1. Base with Abaddon Black
2. Highlight the edges with Stegadon Scale Green
3. Highlight sharp edges and fine points with Fenrisian Grey

Blue-Green (Armour Panels)

1. Base with Sotek Green
2. Shade the recesses with Drakenhof Nightshade
3. Highlight the edges with Sybarite Green

Grey (Armour Ribbing)

1. Base with Mechanicus Standard Grey
2. Shade the recesses with Nuln Oil
3. Highlight the edges with Dawnstone

Silver (Details)

1. Base with Leadbelcher
2. Shade the recesses with Nuln Oil
3. Highlight the edges with Stormhost Silver

For grenades, replace Nuln Oil with Athonian Camoshade

For a rust effect, layer Skrag Brown thinned with water

Orange (Cloth)

1. Base with Jokaero Orange
2. Shade the recesses with Agrax Earthshade
3. Highlight the edges with Kislev Flesh

Brown (Leather)

1. Base with Rhinox Hide
2. Shade the recesses with Agrax Earthshade
3. Roughly highlight the edges with Skrag Brown
4. Finer highlight with Ushabti Bone

Red (Lenses)

1. Base with Mephiston Red
2. Shade the recesses with Agrax Earthshade
3. Layer the middle with Evil Sunz Scarlet
4. Highlight with Wild Rider Red
5. Point highlight with Fire Dragon Bright

Gold (Details)

1. Base with Retributor Armour
2. Shade the recesses with Agrax Earthshade
3. Highlight the edges with Stormhost Silver

Blue (Plasma)

1. Base with Sotek Green
2. Shade the recesses with Drakenhof Nightshade
3. Highlight the edges with Temple Guard Blue
4. Finer highlight with Baharroth Blue
5. Highlight points with Baharroth Blue mixed 1:1 with White Scar