Because people are keeping losing their hard-earned skins in their own skin list.

The guide is made in such a manner so in each section there is a snapshot of vanilla (read: unmodded DLC-less) paint jobs menu.
Everything you see in your game, but don't see on screenshots from this guide, is either a DLC content or a modded paint.

Paint job names are written as seen in default English version of the game at the time of the writing.
DLC pages might contain somewhat different names - in truth, these will be the very same skins.

DLC names are written as seen in default English Steam at the time of writing.
Different DLCs had different names. Notably, Kickstarter was known as Charity for some time.

vanilla
East Bloc Grey & White
Danger Red & Yellow
Roman

DLC
Digital Harvester White - Kickstarter DLC
MC Foreman Black & Red - Kickstarter DLC
Corp VP Black & Gold - Kickstarter DLC
Laser Weapon - Kickstarter DLC
Mining Crew Hardcore - Kickstarter DLC
Space Race - To the Stars DLC

vanilla
Digger Yellow
Hazard Orange

DLC
Locomotive - Fantabulous Contraptions DLC

vanilla
Research White & Orange
Experimental Grey

DLC
no DLC skins

vanilla
Liberty Red, White & Blue
Pastel Pink & Purple
Inverse White, Red & Blue
Dusk Wave
Egyptian

DLC
Warbird - Weapons of War DLC
Shinobi - Warriors of Future Past DLC
Falcon Mecha - Falcon Genesis DLC

vanilla
Black Ops Black
Digital Desert Camouflage

DLC
Iron Hunter - Weapons of War DLC
Shogun - Warriors of Future Past DLC
Falcon Mecha - Falcon Genesis DLC

vanilla
Luxury White & Black
ePower Black & Red

DLC
Roswell - To the Stars DLC
Dirigible - Fantabulous Contraptions DLC

vanilla
Junkers Turquoise
Pure Rust

DLC
no DLC skins