Cyborg

Cyborg is a legendary skin from the Sci-Fi collection. It's drawn for the classic (Steve) model with 4-pixel arms, so choose that arm type when you apply it.

The palette is a dark grey top and dark blue legs. Look for a lit helmet visor. Download the 64×64 PNG, then upload it under Skins in the Minecraft Launcher for Java Edition, or import it from the Dressing Room in Bedrock Edition.