While there are rumors circulating as to what form a potential Borderlands 2 expansion might take, Gearbox's Randy Pitchford has confirmed that more DLC will be forthcoming outside of the four promised Season Pass content dumps.
Speaking to Kotaku, Pitchford confirmed that Season Pass DLC isn't where the fun ends.
"We will have other, non-season pass related DLC," Pitchford said. "The stuff we're planning and working on for the Campaign DLC Season Pass is big DLC stuff - more like [the original Borderlands' Knoxx."
He goes on to use the forthcoming Mechromancer class an an example, which is available from October 16. "Since we finished the game we've started with some new ideas that we expect will show up in DLC."
"Some new vehicle types are on-deck."
So it looks like while the Season Pass DLC will be larger, campaign driven additions, the non-season pass material will be new classes and vehicles.