Valejo has all WWII paint you can imagine. Most of them are even named, for example: German Camouflage Red Brown, German Tank Grey, Afrika Korps Sand Yellow, etc.
For example, all you need to do is decide which year you want your Luftwaffe units from - since Luftwaffe colors changed during the War depending on which season (Summer or Winter) and Theatre of War.
Luftwaffe paintings are named RLM and then a number, for example RLM 65 or RLM 65 A (grey).
As the War progressed, various camouflage paintings became less available due to shortages in general.
Most Tank models in Late 1944 and Early 1945 were from the production line painted overall Tank Grey since this paint was still plentyfull.
This color was also perfect for City Fighting.
Frontline units needed to repaint their equipment with everyrhing they could find or capture from the enemy.
You might find inspiration here:
Panzer Colors I
Panzer Colors II
Panzer Colors III
Messerschmitt Bf 109 in action
Ju 87 Stuka in action
All of the above are from Squadron/signal puplications
Multiple other books are available from this company.
Also check out:
The Eastern Front - Armor Camouflage and Markings 1941 to 1945, by Steven J. Zaloca & James Grandsen
I use waterbased paint from Valejo and acrylic paint from Humbrol.
After painting is dry, I add multiple layers of Matt Spray Varnish for further protection against wear and tear.
You can check out on this forum:
Global 1940 Game Report Thread. There you’ll find some pictures of the units I have in my Axis & Allies game.