Skin Tone Cakes
Most of this page is exactly what the name says, brown and beige single colour cakes for laying down a flat, realistic skin colour: TAG's Brown, Mid Brown, Beige, Earth, Rich Ivory and Bisque, Diamond FX's Essential Brown and Essential Spirit, Fusion's Henna Brown and four Cameleon Base Line browns from Espresso to Macchiato Brown.
A few outliers
Three products here are not skin tones by name: Diamond FX's Essential Black Eye and Cameleon's Bloodrain are SFX bruise and wound shades, and Cameleon Metallic Coloured Yellow is a shimmer colour rather than a skin tone. Worth knowing if you are shopping this page for realistic skin work specifically.
For a flat black or bruise base to work from instead, see theatrical and cosplay make up. For the same brands' other single colours, see base colours cakes.