Probably the line of B&D laser leveling products I designed from 2001-2007. After a year of focus groups and observational field research, we invented the category and then developed over 20 products to support the various wants/needs. I developed North American specific products for CA/US/SA and then a complementary suite of products (most overlapped but some were regionally specific) for the EU/AUS/NZ.
In that 6 year period the company saw over USD300M in global sales of the various products, we won numerous industry awards (CEA, CR, Castorama, etc) and three of the products are still on the shelves 10 years later…but, the reason I think this family is my most successful is because two of the products still for sale were the only ones for which I was able to implement zero-waste packaging.