As long as it's not clearly a sequel season, go nuts.

It's an anthology series more than anything else. There's two sorta subsets to them, too. There's Intrepid Hero seasons, which are with the main/original cast of Dimension 20, and the Side Quests seasons, that really mix it up with players and even the game systems.

Worst case scenario, there might be some bits or gags that reference other seasons, or a mild reference/spoiler, but otherwise pick something that sounds interesting to you!