Since their introduction in 1998, there have been over 9,500 different Hotwheels models produced, including variations. Each year sees a release of new models to replace the previous year's collection. Each year there are First Editions and short sets to collect, as well as the standard models set.

Each model has a unique identity: official name, series name, year, and SKU number. A full checklist, with many high quality photos, can be found at the official collectors website:

http://www.hotwheelscollectors.com/showroom/checklist/

At any time, you can find thousands of Hotwheels models for sale on eBay -  it might be rather daunting to attempt to collect the entire production, but you could start with a particular set, or collect by theme. Hotwheels