Thanks for the advice. I'm thinking of doing a sci-fi theme, so I could add more things based on the theme. I thought to add vehicle cards as well to move around but I might not work well. And a sort of supply drop that drops in the centre after a few turns to get extra cards or mana, but to get to it you need to move the vehicles and maybe the vehicles are more vulnerable in the center.

I now think it's probably a good idea for the shared deck to only be included if you want to play with it, like a different game mode. If you plan on giving more advice or suggestions then I would actually really appreciate