There are several types of deck related products that are sold as systems. The most common are deck railing systems. Manufactured rail systems are usually sold as kits and include an assembly of parts. These kits are designed to fit a certain length of rail section usually 6' and 8'. Most kits include a top and bottom rail, balusters, and attachment hardware for the post and rail connection. Rail posts are usually sold separately. Some rail systems are designed to support glass panels or to keep cable rails in tension.
Deck water drainage systems are also sold as an assembly of parts. Each system is designed differently. Usually there is some kind of channel install along the bottoms of the joists to attach panels into. Sometimes there are also gutters included that are designed to carry the water away from the deck.
Hidden faster systems are used to attach decking without showing exposed nails or screws. These are usually clips that screw into the joists and fit into a groove running down the side of the decking. This is common for many brands of composite decking and exotic hardwoods.