Armor

Base Mechanicus Standard Grey or Dark Grey
Shade/line with Black Templar
Wash with Grim Black : 1:2 Speedpaint Medium

Gold

Liberator Gold then Reikland Fleshshade

Eyes

Raging Sea and then a little bit of Bright Sapphire and White to highlight

Metals

Leadbelcher & Basilicanum Grey

Leather

Base Catachan Fleshtone
Glaze the edges with Mournfang Brown
Highlight with Steel Legion Drab
...
Alternatively, XV-88 all over

Reds

Mephiston Red or Khorne Red