One (1) tube of 100 ml of each color:
• 1 white,
• 1 trichromatic black,
• 1 primary cyan,
• 1 primary magenta, and
• 1 primary yellow (or equivalent primary colors).

Recommended brands: Pebeo Studio Gouache (100 ml is cheaper), or any designer /professional gouache (15 ml or more) such as: Holbein Artists' Gouache, Daler-Rowney Designers Gouache, etc.
Possible Alternative Brands in Sets: Pebeo Studio Gouache Primary Set (5 x 100 ml), Artist's Loft™ Fundamentals™ sold by Michael’s or Reeves Gouache Paint, 12 Count are more affordable alternatives although they produce much inferior outcomes.

Pebeo Gouache Studio Set