There are currently three "core sets":
• Autobot Core Set
• A Rising Darkness
• War on Cybertron

There are also two "expansions":
• Infiltration Protocol
• Dawn of the Dinobots

The core sets can be played by themselves, while the expansions require at least one of the core sets. Of course, all of them can also be used together!

Additionally, each set has an associated "Bonus Pack". These were originally included with pre-orders, but can still be purchased after the fact.

All sets are available at Renegade Game Studios's store, or on their Amazon store.

Character cards fit perfectly in 76 x 102 MM sleeves. I use these ones by Sleeve Kings.

Combiner characters fit nicely in 4 x 6" sleeves. I use these ones by BCW.

All other cards are traditional trading card size, 63 x 88 MM.

Renegade Game Studios has made all of the DBG rule books available online. They have full instructions on how to play. Here are links to them in order of release.

• Autobot Core Set
• A Rising Darkness
• Infiltration Protocol
• Dawn of the Dinobots
• War on Cybertron
• Clash of the Combiners (coming soon!)

If you prefer a video, Board Game Coffee has a good "how to play".