All I'm finding is:
- Dark Green
- Black
- Tan
What other colors could I go with them? I could easily just make them my own scheme, but I'd like to somewhat stick to their backstory.
Dark Angels Chapter's Pre-Heresy Colour Scheme
Prior to the Horus Heresy, during the Great Crusade, the Power Armour of the Dark Angels Legion was coloured jet-black. Not long after the Legion's Primarch was reunited with the warriors of the I Legion, a wedge began to be driven between the Calibanite Dark Angels and their Terran-born brethren.
Veteran Dark Angels are commonly found wearing hooded cloaks and tabrads; this symbolises their shame over what the Fallen Angels had done near the end of the Great Crusade. Cloaks and hoods are worn by the Veteran Dark Angels and the Chapter's Inner Circle because they have learned enough about the Dark Angels' history, and thus their shame, prior to obtaining their rank within the Chapter.
Veteran Dark Angel Colors
After the Heresy, the bulk of the Chapter began to appear in dark green armour, while the 1st and 2nd Companies' panoply remained jet-black in honour of the original Legion colours. The Deathwing Company later re-coloured their armour to bone-white in honour of a battle fought long ago but after the Heresy. Chapter legend states that a band of Deathwing brethren returned to the world of their birth, only to find their people enslaved to a large Genestealers cult. Abiding by the traditions of their people, the brethren repainted their armour white, symbolising that they were dead men walking - ghosts - setting out on their death-quest to rid their world of the Genestealers' taint. Since that day, the Deathwing have continued to wear their Terminator Armour in bone-white colours, in solemn remembrance of the sacrifice of their predecessors.
Post Heresy Colors
Apothecaries of the Dark Angels keep their entire armour painted black except for the backpack, groin and torso armour, which are all bone-white. They have a red vertical stripe painted down the centre of the helmet.
The badge of the Chapter is a winged sword on a green roundel, which was the ancient icon of The Order. Variants of this symbol exist for the Deathwing and Ravenwing Companies, the former depicting the winged sword as broken, the latter a sword held by a single wing and raven's claw. The 10th Company, the Chapter's company of Scout Marines, uses the Dark Angel Sword but without the wing device, to symbolise the fact that the Scout Company comprises Chapter Neophytes, who have yet to "earn their wings" as full Dark Angels.