On the occasion of the platform's Spring Sale, Steam is offering free play on Tiny Tina's Dragon Hold. This is the most famous Borderlands 2 DLC, which became a standalone game to promote Tiny Tina's Wonderlands.
Tiny Tina's Assault on the Dragon Keep: A Unique Adventure in the Wonderlands (this is the whole title) will be available to play immediately or to wait for better times to get it.
To enjoy Borderlands 2, you must not have Borderlands 2, and you must be willing to engage in all its modes, including the cooperative one.
"The queen has been captured, and her kingdom is in jeopardy," Tiny Tina's dragonhold says. Be careful: Tina's merry and chaotic ways may alter your destiny in an instant."