As long as I've been doing German figures, I've always painted the belts, and the over the shoulder (suspenders?) straps just black. I've seen many pics of them as different colours, were they all black normally? Were they different for coats that were for say, having an Oak or Pea Pattern cammo? and same question for ammo clip holders that go around the waist, basically black or perhaps a dark leather colour?

The vast majority were black. The straps for the gas mask canister were web though,and so field gray or khaki or tan.
I always paint the belts a dark gray so you can outline the low areas or edges in pure black.
J

Thanks Jerry for the tip about painting the belts dark grey.

There was black leather, there was black ersatz, there were brown inserts on the suspenders, there were later canvas inserts, there were also shortages leading to the issue of tropical items of canvas and webbing. I recommend the Osprey MAA on German combat equipment by Ron Volstad and the various photo books of surviving items. Really shows the variety.

At the back, where the "Y" is formed with the steel ring, and the strap ends are folded over to sew to the ring, the un-dyed reverse side of the leather is revealed, and it's usually buff/light tan (bare leather color). But these are just small portions where the strap wraps around the ring.

https://www.worldwarsupply.com/cart/image/cache/Field%20Gear/German%20Y%20Straps/web_3805-500x500.jpg

Later in the war similar-looking straps were made of canvass webbing.

Thanks so much every one, I like the idea of using a dark grey, then the black to do the deeper areas, this has been most helpful

In some cases, officers were issued brown leather belts.