What colours and sizes does the rainbow come in?

The rainbow comes in nine different colours and four different sizes. However, not every colour comes in every size.
The large 12-piece rainbow comes in classic, pastel, natural, monochrome, forest green and meadow green.
The medium-sized rainbow consists of 10 pieces and was previously only available in the world of numbers variant and now brand new in the variants neon pink and neon green.
The 6-piece rainbow is available in the colours classic, pastel and nature.
The small 6-piece rainbow is available in the colours classic, pastel, nature and monochrome.