The most popular boards used are:
B-Flute Single wall in a 125g and 150g paper weight. This is typicaly used for smaller boxes and ecommerce boxes.
C-Flute is a course flute single wall used in larger boxes where more strength is required but doesn’t warrent double wall strength.
BC-Flute is a double wall board made with a B and a C flute to give it strength. This is made with 125g , 150g and 300g paper weights. The 300g is often used for heivy engineered componants.